This was a classic play where big tech used XMPP to grow their user base, but as users changed left to escape various paper cuts (ads in the UI, lack of utility

This was a classic play where big tech used XMPP to grow their user base, but as users changed left to escape various paper cuts (ads in the UI, lack of utility, etc...), big tech realized they could not force people to stay on their platform. So, big tech does what it does when it has more to lose than gain - it went closed.