It’s not so much that they’d take it over, it’s that they’d extend it (in incompatible ways) and exploit it. XMPP still exists and there are bunches of clients for it, but it’s basically where it was 15 years ago when Google et al first adopted it. Ploum’s got some great pespectives on the XMPP experience at ploum.net/2023-06-23-how-to-kill-decentralised-ne… and there are a lot of parallels.