The concepts of innovation and disruption were discussed at length when I was in grad school, and I don’t disagree about its overuse- since leaving the master’s program I’ve heard it abused ten times for every time someone used it correctly. That being said, butchering the concept does not mean it will go away.
The reason disruption is important is that technological progress can be destructive (and destruction itself is not necessarily a bad thing). Our economy is based in large part on goods and services that built up their own infrastructure to provide information and logistics to both the providers and consumers of said goods and services. Journalism is one example. In order to bring news to anyone who wished to consume it, first newspapers were printed and distributed. Then TV news was broadcast. Now most of this information is available online.
Each of these steps required a buildup which was, at least, very expensive. And the subsequent step rendered at least some of the previous one obsolete. With TV news, newspapers had significantly less reason to publish multiple editions per day, as one trying to get the latest news would just turn on the TV. To compensate, newspapers tended to skew a little more local, in order to provide services (classified ads, for example) that couldn’t take advantage of the incredibly expensive (and at the time closed-off) TV landscape.
The difference between the move into TV and the move online is that newspapers don’t do anything better than the internet (save provide scrap paper for packing boxes). Classifieds are cheaper and have better reach. News is faster. Advertisements are better targeted. When the incoming technology is simply superior to the old one in every way, it is disruptive. The only other thing Christensen specifies is that the buildup of said technology occurs in a way such that no one sees it coming.
The internet’s high rate of access and incredibly low cost have made it a breeding ground for disruption. Uber, Tesla and AirBNB all use the internet as a replacement for systems that before would have been out of reach to singular people. This does mean people conflate disruption with “successful new business”. But just because people don’t understand what it means doesn’t mean it isn’t happening.