The difference is nobody used XMPP before and after Google integrated it. People are using the fediverse. I don't think people already using the fediverse will ever migrate to threads. If anything, people may realise that they can talk to threads people and leave Meta's system. Even the BBC and the European Union have their own instances. I cannot see them migrating to Threads whenever Meta messing with politics is a known issue
We know what META is about and what they do. We came here because we didn't want to be treated as products and used as experiments constantly watched by "AI algorithm".
The smartest thing anybody ever said to me is, "don't let a pimp have access to the battered woman's shelter."
Almost all of us are here because we have either always thought that, or grew to think that.