Also XMPP sucked when it came to mobile devices - maybe the right answer was to have a RFC for an improvement to the standard rather than create environments outside of it, but I can see a reasonable argument for biasing towards development speed.
Google kept XMPP support the longest - I think they closed it when everyone else was closed and the others were using Google's remaining XMPP support to farm over Google users while not allowing Google access to do the same. It's a problem with incentives - there was a time when cross service compatibility was important.