XMPP, then. it’s the continually inventing new protocols (insert XKCD comic) that i’m protesting against.
"New" is relative of course, XMPP is 27 years old. Still, XMPP lacks official support for something as basic as "I want to log in on a new device and see the old, encrypted messages that are on my other devices".
IRC itself is a reinvention of `talk` and BBSware. For as long as there will be new use cases, there will be new protocols.