I was interested until he brought up that matrix was just a reinvention of an existing idea. no, xmpp cannot do everything that matrix can. have you ever tried getting consistency of history in xmpp? it's absolute garbage. his warnings about the fediverse are on point though. I do wonder if matrix will end up suffering the same fate when Reddit offers to federate with them. The matrix protocol is already brittle as it is, and compatibility even between good faith implementations of existing servers is hard.