I think initially there will be some limitations. And there are definitely flaws and limitations with activitypub. Maybe this will push the protocol forward to be better.
But if they really break it, why not fork it and not worry about Threads?
I think it’s funny that people think that Meta will kill the Fediverse. Just like Google “killed” xmpp. I think neither is true.
Adam Mosseri (the actual person behind Threads) in the podcast that I linked in a different comment said that’s one of the goals of Threads.
I doubt it’s going to happen in the next week or two but it seems like they are embracing activitypub.
It’s a pretty solid interview. It’s a podcast called hard fork.
Of course Adam knows how to PR and take some of the things he says with a grain of salt but he seems pretty candid.