The problem with a 45% increase is that people who actually use adblockers is only around 10-20% of their userbase, but more intrusive ads will probably affect the other 80-90% of people and make at least some of those people use youtube far less as well. It also primes the market for a youtube competitor to come along and offer the same service, but with far less intrusive ads. I don't believe any company can be "too big to fail." I don't think this will be some massive overnight thing though, but it might start a chain reaction that leads to people using something else in the future. (Like if something like TikTok started letting people make long form content in response to this, it could cause a lot of people to move to their platform from youtube)