As Peter Thiel, one of Facebook’s prominent investor, put it: “Competition is for losers.” Yep, those pseudo “market is always right” people don’t want a market when they are in it. They want a monopoly. Since its inception, Facebook have been very careful to kill every competition. The easiest way of doing it being by buying companies that could, one day, become competitors. Instagram, WhatsApp to name a few, were bought only because their product attracted users and could cast a shadow on Facebook.
But the Fediverse cannot be bought. The Fediverse is an informal group of servers discussing through a protocol (ActivityPub). Those servers may even run different software (Mastodon is the most famous but you could also have Pleroma, Pixelfed, Peertube, WriteFreely, Lemmy and many others).
You cannot buy a decentralised network!
But there’s another way: make it irrelevant. That’s exactly what Google did with XMPP.