Christensen observed that when upstart entrants attacked successful incumbents by adopting the incumbents’ models and technological solutions — what he called a “sustaining” strategy — they tended to fail.

In contrast, entrants tended to succeed by combining a business model tailored to the needs of a relatively less attractive market — the entrants’ foothold — with an ability to improve their original solutions in ways that allowed them to provide superior performance that incumbents were unable to replicate — the upmarket march. Christensen called the union of these two elements a “disruptive” strategy.

* Source: Deloitte