startups don't have a choice but to do the "disruptive innovation" play
because of limited resources and access to existing markets, all startups that find success, even if they aren't try to follow, do follow the "disruptive innovation" track
ie. find niche customers who benefit from a niche aspect of an otherwise substandard product
ie. "disruptive innovation" isn't a prospective "strategy for startups to maximize success", it's a retrospective description of high growth startups
(which, can be applied in a prospective sense as a filter for likelihood of high growth - but probably better for VCs and day-0 entrepreneurs, than in-the-thick-of-it-startups)
also, "disruptive" is not "better"
it's just an emotion-laden word that Christensen chose to describe a phenomonen