I love XMPP and am hopeful for its future with what the teams behind Movim[0], and Fluux[1] are doing. It was a tremendous shame that Matrix didn't improve upon XMPP and instead did their own thing. I continuously wonder what would the XMPP ecosystem look like, if the millions of dollars of funding Matrix initially had (what a waste) went to XMPP instead?
[0]: https://movim.eu/
It makes sense. It's old, crufty mix of extensions, which nobody actually wants to be that modular for a chat client, because that just gets you into mess of what server/client supports