@shane the same applies for Signal, they can change the servers too. You also rely on server admins, most of them volunteers, to put additional resources. I don't see Signal's approach as a single point of failure as they are already using a cluster of servers, while XMPP servers (at least Prosody) lack this feature AFAIK. If anything, I find the crowdfunded approach of community proxy servers more resilient. My point is, decentralisation is good, but in this case it wouldn't help.