Confidential / Teaching Note

DISRUPTION
/ Why incumbents lose

A working brief on Clayton Christensen's theory of disruptive innovation — the patterns by which dominant firms, doing everything textbooks recommend, lose their markets to upstarts they could have crushed.

Figure 0 · The puzzle in one image

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Chapter One

The Innovator's Dilemma: well-managed firms, well-executed strategies — and still they fall.

Clayton M. Christensen, then a Harvard Business School professor, opened his 1997 book with a question that economics had never cleanly answered:

"Why is success so difficult to sustain?
Why do good managers, doing the right things, lose to firms that look smaller, slower and worse?" — Paraphrased from Christensen, 1997

The empirical anomaly. Disk-drive industry, 1976–1995: market leaders changed at every architectural transition (14″ → 8″ → 5.25″ → 3.5″).
Not laziness, not arrogance. Failed leaders were studied, customer-focused, analytically rigorous.
The thesis. The very practices that make great firms great — listening to your best customers, investing in highest-margin products — are what makes them vulnerable.

Figure 1 · The dilemma, schematically

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Type A

Sustaining innovation — what incumbents are built to do.

Sustaining innovation makes a good product better, along the dimensions the most demanding customers already value.

Direction. Up the existing performance curve — faster CPUs, sharper sensors, larger drives, longer-range jets.
Customer. The firm's best, most profitable customers — the ones the sales force actually talks to.
Economics. Higher margins, higher prices, fits cleanly into existing channels and cost structures.
Track record. Christensen's data: incumbents win sustaining battles roughly nine times out of ten.

"In every case, the incumbents won the sustaining-technology contests, and were defeated in the disruptive ones." — The Innovator's Dilemma, ch. 2

Figure 2 · Sustaining trajectory

Sustaining innovation is compatible with the incumbent's resources, processes and values. It feels like progress, because it is progress — just not the kind that protects you.

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Type B

Disruptive innovation — starts inferior, in places no one important cares about.

A disruptive innovation is initially worse on the metrics mainstream customers value, but cheaper, simpler, more accessible, or convenient on a different axis.

Two entry vectors. Low-end disruption: serve over-served customers who'll accept "good enough" at a lower price. New-market disruption: serve non-consumers who weren't using the product at all.
Trajectory. Improves rapidly along its own curve. Eventually meets the needs of mainstream customers — from below.
Why incumbents miss it. By every metric they track, the new thing is a downgrade.

Figure 3 · The market-segment ladder

High endMost demanding customers, premium price, highest margins25%

Mid marketMainstream segment, standard features40%

Low endOver-served, price-sensitive — incumbents flee upward25%

Non-consumersCouldn't afford or use the product before — the largest unmet market~10% → ?

Disruptors enter at the bottom rung, then climb. Incumbents retreat upward, vacating margin-thin segments — a rational decision that hands the staircase to the attacker.

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The defining diagram

Technology improves faster than customers' ability to absorb it. The disruptor crosses the demand line from below.

Figure 4 · The S-curve crossover

Two slopes, not one market. Performance improves on the supply side; need improves on the demand side — but the two have different rates.
The overshoot. Incumbents push capabilities past what customers can use. Marginal improvement loses its marginal price.
The crossing. The disruptive curve, starting far below, eventually intersects the demand line of the low-end segment. That segment switches.
Then it climbs. Each year the disruptor crosses the demand line of a higher segment. The incumbent flees upmarket until there is nowhere left to flee.

Performance overshootCrossoverUpmarket flight

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Two canonical files

Kodak vs. digital cameras. Integrated steel vs. minimills.

Case A · Kodak (1975–2012)

Invented the disruptor. Steve Sasson, Kodak engineer, built the first digital camera in 1975. 0.01 megapixels.
Knew the threat early. Internal memos from the 1980s explicitly forecast film's death.
Couldn't switch. Film and chemistry margins were ~70%. Digital was a hardware commodity. The board kept choosing film.
Endgame. Filed Chapter 11 in January 2012, the year smartphone cameras became the default.

Case B · Steel minimills (1965–2000)

The dirty entry. Minimills (e.g. Nucor) used electric arc furnaces and scrap. Output: low-grade rebar. Big steel happily ceded it.
The climb. Rebar → angle iron → structural beams → sheet steel. Each step, US Steel and Bethlehem retreated upward, declaring the abandoned segment "unprofitable."
The end of the staircase. By the 1990s minimills made everything. Bethlehem Steel filed for bankruptcy in 2001.
Pattern. Same rational logic, same fatal sequence.

"There was nothing wrong with Kodak's strategy. It was correct — for the customers Kodak had."

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The hidden trap

The incumbent's most profitable customers do not want the disruptive product. So building it is, by every quarterly metric, a bad idea.

Customer voice. Big customers say: "Don't waste R&D on a worse, cheaper version. Make ours better."
Sales force. Compensation tied to deal size. Disruptive product sells for 1/10th the price — nobody will pitch it.
CFO arithmetic. Incremental dollar of capex earns more in the high-margin core than in the unproven low-margin frontier. The DCF says no.
Stock-market discipline. Public markets punish margin compression. Self-cannibalisation looks like value destruction in any single quarter.
The tragedy. Each individual decision is correct. The aggregate is suicide.

Margin per unit

High margin / Top customers

Existing premium products. Sales force loves it. CFO loves it.

DEFEND

High margin / New customers

Premium expansion. Often pursued; rarely disruptive.

EXPAND

Low margin / Top customers

Cannibalising your own premium — institutionally forbidden.

FORBIDDEN

Low margin / Non-customers

The disruption zone. Looks like a rounding error. Until it isn't.

IGNORED

Customer importance →

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Christensen & Overdorf, 2000

Resources, Processes, Values — the three layers that make a mature firm incapable of disruptive moves.

Layer 1 · Easiest to change

Resources

People, capital, IP, equipment, brands, customer relationships. A mature firm has more of these than the disruptor — this is rarely the bottleneck.

Layer 2 · Harder

Processes

How decisions get made: market research, budgeting, product development, sales compensation. Calibrated to the existing business; misfires on a new one.

Layer 3 · Almost impossible

Values

The criteria by which the firm decides what is "attractive" — minimum gross margin, deal size, growth threshold. A $10B firm literally cannot care about a $50M opportunity.

A mature firm with $10B in revenue and a 40% gross-margin floor will, by definition, refuse to fund a project that promises $80M of revenue at 15% margin — even if that project will become a $20B business in eight years.

Resources can be redeployed. Money and people move.
Processes can be retrained. Slowly, painfully.
Values almost never change. They are what the firm is. Asking a premium brand to embrace low-margin is asking it to stop existing.
Implication. Disruptive responses must come from a separate organisation with its own RPV stack. (See slide 11.)

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Four contemporary cases

The same shape, different decade.

Case 1 · Streaming, 1997–2010

Netflix vs. Blockbuster

Netflix entered as DVDs-by-mail — slower than walking to a video store. Blockbuster (9,000 stores, $5B revenue) declined to acquire it for $50M in 2000. Streaming pivot in 2007. Blockbuster filed Chapter 11 in 2010.

Case 2 · Mobility, 2009–present

Uber / Lyft vs. taxi medallions

Entered serving non-consumption (people who'd never call a cab). Taxi industry dismissed as illegal toy. NYC medallion value: $1.3M (2013) → ~$80K (2020). The classic new-market disruption signature.

Case 3 · Automotive, 2008–present

Tesla vs. Detroit

Atypical case. Tesla entered at the top ($109K Roadster) — not a textbook Christensen disruption. But it built a parallel RPV stack (vertical integration, software-first, direct sales) that the legacy OEMs cannot replicate inside their existing firms.

Case 4 · Pharma, 2020–present

mRNA vs. classical vaccines

Moderna and BioNTech — tiny, decades-loss-making — held the platform when COVID hit. Classical vaccine giants (Sanofi, Merck) couldn't pivot from protein/inactivated platforms in time. A textbook example of new-platform disruption accelerated by external shock.

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A serious critique

Not every collapse is "true Christensen disruption." Selection bias and definition drift have weakened the theory.

Jill Lepore, The New Yorker (2014). "The Disruption Machine" argued Christensen's case studies were cherry-picked; many "disrupted" incumbents in the disk-drive data later recovered.
Selection on the dependent variable. Studying only firms that failed risks confirming any plausible-sounding story.
Definition drift. Christensen himself complained, in 2015 (HBR, "What Is Disruptive Innovation?"), that "disruption" had become a buzzword applied to any successful startup.
Notable mis-classifications. Uber, by Christensen's own definition, was not disruptive (entered mainstream urban core, not low end / non-consumption).
Empirical limits. King & Baatartogtokh (MIT Sloan, 2015) re-examined 77 Christensen cases — found only ~9% fit all four elements of the theory cleanly.

"Disruptive innovation has become a competitive imperative. It is also a theory that cannot be falsified, since any contrary evidence is simply called something else." — Jill Lepore, The New Yorker, June 2014

"The problem with conflating a disruptive innovation with any breakthrough that changes an industry is that different types of innovation require different strategic approaches." — Christensen, Raynor & McDonald, HBR, December 2015

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If you are an incumbent

Practical responses — mostly organisational, not technical.

1. Spin out, don't bolt on. Create a separate unit with its own P&L, its own values, its own minimum-margin threshold. (IBM PC, Dayton-Hudson → Target, Toyota → Lexus.)
2. Match firm size to opportunity size. A $50M opportunity is a strategic threat to a $200M firm and an irrelevance to a $50B one. Put the project in a vehicle that cares.
3. Fund the cannibal. If you don't kill your own product, someone else will. Apple killing the iPod with the iPhone is the textbook case.
4. Watch non-consumption. Map who is not using your product. That's where the disruption germinates — not in your CRM.
5. Hire for the new RPV. Don't redeploy lifers; recruit people who haven't internalised the old margin floor.

Figure 5 · Spin-out structure

Christensen's prescription is structural: don't ask the antibodies of a mature firm to nurture an alien transplant.

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The verdict

A genuinely powerful frame — sometimes overused, often misapplied, still indispensable.

What the theory does well

Explains a real, recurring pattern: rational firms, looking only at their best customers, ignore inferior threats until those threats are no longer inferior.
Reframes "innovation" from a technology question to a customer-and-business-model question.
Gives executives a structural — not moral — explanation for why their firm is unlikely to invent its own replacement.

What it does not do

Predict which startup will disrupt — only the conditions in which disruption is possible.
Cover all incumbent failures: many die from regulation, scandal, debt, or simple managerial error, not from disruption.
Justify the cult of "move fast and break things" — the theory describes a phenomenon, not a moral imperative.

"The right question is not 'are we being disrupted?' but 'are our governing values so tightly bound to our existing customers that we cannot see anyone else?'"

Powerful frameOften misappliedWorth knowing exactly

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Sources, watching, and a parting thought

For further work.

Primary references

Christensen, C. M. (1997). The Innovator's Dilemma: When New Technologies Cause Great Firms to Fail. Harvard Business School Press.
Christensen, C. M. & Overdorf, M. (2000). "Meeting the Challenge of Disruptive Change." Harvard Business Review, March–April.
Christensen, C. M., Raynor, M. & McDonald, R. (2015). "What Is Disruptive Innovation?" Harvard Business Review, December.
Lepore, J. (2014). "The Disruption Machine." The New Yorker, 23 June.
King, A. A. & Baatartogtokh, B. (2015). "How Useful Is the Theory of Disruptive Innovation?" MIT Sloan Management Review, Fall.
Bower, J. L. & Christensen, C. M. (1995). "Disruptive Technologies: Catching the Wave." Harvard Business Review.

YouTube — live searches

Clayton Christensen on the Innovator's Dilemma →
Lectures, HBS interviews, primary sources
Disruptive innovation explained →
Animated explainers, case-study breakdowns

"The theory of disruptive innovation will not save you. It will only tell you how, and why, you are likely to die." — Closing thought

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