I think this would have certainly been in the cards in the past, but at least for the moment there is regulatory backlash against anything seen as anticompetitive, especially buyouts like you referenced. (I Work with M&A teams)FB is having to pay significantly above market to attract and retain talent, and the use patterns are not well aligned to homegrown competitors to tik tok. Some might argue this is why such a big bet is being placed on the “metaverse” business plan. But these trends may be the biggest long term challenge they have faced since the rise of mobile.
There's no chance in hell regulators let them get away with it. They couldn't even acquire Giphy, let alone something more serious.
They can’t buy TikTok which is the big thing right now.
There will be a new big thing in five years or so. Meta makes enough money to bridge to that. They don't need to win every generation of social media.