The best-run company can still miss the market that does not yet pay it to listen.

Christensen's first move is to normalize incumbent success. Established firms often lead sustaining changes because those changes improve the dimensions their best customers already value. Their engineering talent, sales relationships, planning routines, and capital discipline all line up behind that work.

This matters because it blocks a shallow explanation. If leaders repeatedly win on sustaining improvements, the eventual failure cannot be reduced to incompetence. The more useful question is what kind of opportunity would fail to look attractive inside an organisation built to serve demanding, profitable customers well.

The section becomes sharper when Christensen ties innovation choice to market size and customer demand. A disruptive trajectory often begins in a smaller or less profitable segment, with buyers who value a different mix of attributes. To a well-managed incumbent, that looks like weak demand, weak margins, and weak use cases.

That is why the dilemma is structural. Managers are not ignoring evidence; they are obeying the evidence their current business is designed to treat as credible. The same filters that protect returns in the core can make a new market appear too small to deserve serious commitment.

Christensen pushes past the heroic-manager myth by showing how firms depend on customers and investors for resources. The most powerful customers influence which performance improvements get prioritized, which products feel worth building, and which opportunities seem responsible enough to fund.

This shifts the strategic question. Instead of asking whether leadership has enough foresight, ask which external demands the company cannot easily refuse. A firm may understand the new trajectory in theory and still be unable to justify it within the economics and expectations of the current business.

A disruptive technology rarely enters by beating the incumbent on the incumbent's favorite measure. It often looks smaller, slower, simpler, or less capable to the mainstream buyer. Christensen's argument is that this apparent weakness is exactly why leaders deprioritize it until the alternative performance path improves enough to invade the core.

For product and market work, this is the diagnostic test worth carrying forward. When a new offer looks inferior, separate 'inferior on the current metric' from 'incapable of anchoring a different job.' That distinction determines whether the newcomer is noise, a niche, or the front edge of a new curve.

By the end of the chapter, Christensen has prepared the reader for why disruptive work often needs a different organisational home, cost logic, or customer set. A mature core business is optimized to reject opportunities that are too small, too low-margin, or too misaligned with what current customers request.

The practical lesson is not to stop serving the core. It is to notice when the core's decision rules are being mistaken for universal truth. A new trajectory usually needs protection long enough to be judged by the job it serves, not by the standards of the business it may later unsettle.