Everybody keeps referencing Ploum and he's got a great blog - I have him on my RSS feed. But he's wrong about this. Google didn't kill XMPP because it was never anything more than niche to begin with. Google Talk was like 99% of XMPP users from the very start. It isn't analogous to our current situation.
But here's my trying to make some sort of example- The big company takes a new technology and embraces it - like Meta with ActivityPub. Then they extend it, but in such a way that it isn't compatible with the rest of the format.
So let's imagine how this could be done in ActivityPub. Maybe there are some features on Threads that creates a sort of centralized index of all Fediverse sites. So if you wanted to search for something, Threads was the best. So because of this, many people start using Threads.
Then, extinguish. They kill the standard. So Meta kills ActivityPub and makes it so that everyone who made an account on Threads is locked in.
What happened to the Fediverse in this scenario? Nothing. It will be exactly the same as before. A federated group of instances.
Unless we are scared of thr vast majority of users flocking to Threads should we federated with them, which i sincerely doubt because most people don't trust Meta, then what is the risk? I don't see any.
What is the potential reward? Connecting our communities with millions of people. Millions of people will follow threads and people from Fediverse and will learn about the movement. More connection, more integration with an open protocol.
Everyone is jumping on this anti-federation bandwagon, repeating the same couple sentences they heard someone else put down without any independent thought. I think we live in crazy land sometimes.