Facebook opening up to non-students was the turning point IMHO. Myspace was big, but everybody knew it was trash so not being on it was fine. If you wanted "a profile" otherwise, you needed your own page. That took effort, so only people with something to say bothered with it. Even Twitter was still SMS based and so only for hardcore addicts.
Facebook gave everyone an effortless voice and lordy, do people talk crap.
There's certainly a bubble bursting. You only have to look at all the layoffs.fyi since COVID. I'm just hoping it's happening in a slow enough way that it's not going to take more legitimate companies with it.
AI is the next bubble. It will hit a brick wall either legally or just on functionality (maybe both). I can see uses for targeted models, bespoke to a use case, but training those is too expensive right now. General models are just toys IMHO. Unfortunately it's going to get a few years for everyone to realise.