I'm a little afraid that eventually people are going to get bored of running instances and we're going to converge back on centralisation. That's what has always happened. IRC lost federation in the early 90s with Eris Free net, most webmail providers died and only Gmail and a few stragglers survived, blogs converged towards Medium, RSS feeds took a big blow when Google killed Reader, most big XMPP servers stopped federating, and thus XMPP is mostly dead...