Edit: Please don't downvote OP. It's a good discussion and their opinions are well written
They'll do exactly what google did to XMPP, an alternate chat platform running in the same manner as mastadon and lemmy do. They federated, and since google had more people XMPP users found the majority of their contact lists were filled with google users. Most google based users had no idea what XMPP was.
They embraced it
Google changed the API without stating quite often, at first mildly but then drastically in ways that fundamentally altered the API. Other servers either bent the knee and did whatever google wanted or defederate.
They extended it
Meanwhile, when google changed their api XMPP users lost the majority of their contact list and the google user saw that their friend whose trying to get them to switch just kept disappearing, and lost their chat history. Why would they move away from their google service if XMPP was so shit? People moved away from XMPP too, of course they did. They couldn't talk to their contacts.
In the end, maintaining XMPP got insanely difficult so most servers shut down, and google shut down it'ss XMPP node
They extinguished it
Why would Meta do any different? I can't remember who said it, but that's the company where the quote "competition is for pussies" comes from
The decision to federated is the decision to allow them to hold a knife against our wrist. Sure, they could help out, or they could end the competition. This is suicide.