I tend to think of it more that discrepancies between what the platforms are purported to be, and the actual use patterns and motives are, has grown to a point where it's getting scrutinized and having substantial pushback. Another way of looking at this is the limitations and drawbacks of current platforms are being exposed in unavoidable ways.
Another issue that's gotten some attention but maybe not as much as it deserves is the diversification of social media and generational trends. I think Facebook and Twitter trends older and has become more of a political punching bag, which has led to the sorts of things you're talking about. "Younger" platforms, demographic-wise, have largely gone under the radar and we haven't seen the sort of repositioning and jockeying that we've seen with Twitter and Facebook. So Facebook is trying a sort of pivot (wisely so in my opinion, even though I'm not sure about the nature of that pivot), even as things like TikTok are percolating up into media consciousness. It may not be that social media is saturated it might be that people are migrating, passively or actively, to other platforms that have so far gone unscrutinized by older demographics who tend to use things like Twitter and Facebook.
Who knows though. For me it's interesting to watch. I've never really been involved with either platform, for multiple reasons.
There seems to be growing interested in more decentralized or federated platforms. I'm starting to wonder if these will gain traction sort of slowly and organically as the other platforms churn over time and they're the only things left being stable.