The rest of history. The #XMPP protocol at the time has some glaring inadequacies in some areas, so it had to be extended to cover those use cases. Instead of working with the community at large to converge towards common extensions for logging, device switching, audio/video and conference calls, #Facebook and #Google went with the classic #rugPull, first by defederating their servers (lock users in) and then by switching out of the protocol altogether.