I know that is a popular narrative in the Fediverse community right now, but I honestly find it unreasonable. Google and Meta didn't kill XMPP, they abandoned it and without them it went right back to where it was originally: barely used whatsoever. The Fediverse already has a small, but relatively healthy user base. Meta can abandon ActivityPub or twist it into something unacceptable, but all that will do is bring us back to where we are right now.

All that is irrelevant, though, because the difference is that Meta is legally required to incorporate interoperability with other services and that's why they are going with ActivityPub. Not from the good of their hearts, but because they need to and is in their own self interest to keep alive.

Right now, they are early adopters of ActivityPub and have a very early strong position there. When they federate they will be by several magnitudes the largest instance on the network. Whether we like it or not, they will inevitably be a major player in dictating the future of ActivityPub. Thus, they want to keep ActivityPub alive because they want to make sure that becomes the future EU mandated industry standard for SoMe. Otherwise, some other technology will be chosen, one that might not be lead by Meta, but by Google, Apple or ByteDance.

Note, that I'm not arguing whether this is good or bad, but only what I predict is happening.