Facebook didn't "destroy" XMPP. XMPP was a tiny messaging protocol nobody used, Facebook picked it up for a bit, stopped using it after a while, and then XMPP returned to being a tiny messaging protocol nobody used.
People are acting like Jabber was hot shit when Facebook picked it up, and its present state of irrelevance is because of big bad Zuck. No, no fucker used Jabber and it saw basically no mainstream adoption until Facebook and Google got involved, and as soon as Facebook and Google weren't involved (as it turns out that XMPP actually kind of sucks and its unique features are things end users don't care about) it returned to being a complete irrelevance. A well-intentioned irrelevance, to be sure, but an irrelevance.
Fediverse is the same, mutans mutandis. We're tiny. I know it's nice for us to psyche ourselves up and say that we're going to destroy the big bad corporate media! but in reality we are a niche constellation of social networks that has literally 0.1% of Facebook's user base and whose adoption has been, shall we say, not stellar.