I understand what you mean. I think that the future is uncertain. Maybe matrix will flourish and xmpp will go under or the other way around. Maybe a third option will develop. For example if suddenly 1bn people join the fediverse and mastodon implements the signal encryption protocol for pm’s it could become the new xmpp/matrix.

I believe that both matrix and xmpp have their strength, but what I personally like about xmpp is that it is very lightweight to host.

I hope xmpp will be modernized, aka have encryption by default, have proper metadata encryption, maybe snikket can send traffic through tor by default or something like that or have their own onion-routing. I think that it is a mistake to implement video calls before having very reliable clients with the features mentioned above. Also mastodon could just ship with a xmpp server, i’d like that. So pm’s are through xmpp by default.