> And it doesn't work at all with low power mobile delivery. (It was invented before the iphone.)

This is plain untrue. Yes it was invented a long time ago, but thanks to the extensibility it has evolved over time just as the way people use it has changed. This evolution is a healthy and necessary part of an open ecosystem.

I know it frustrates people that modern features don't work in stagnated clients such as Pidgin and Adium, but modern clients support all the things you would expect.

Servers and mobile clients have supported mobile-friendly traffic and connection optimisations for many many years now.

> There might have been political reasons why google dropped XMPP, but it would also make sense as a purely technical decision.

Google contributed extensions to XMPP, the same way they contribute to other internet standards. I think they were quite comfortable with this. The XMPP-based Google Talk was their longest-running messaging solution after all...

> And it doesn't work at all with low power mobile delivery.

What makes you think so? If Conversations was draining my battery, I would have noticed by now, I'm pretty sure that Facebook Messenger is worse in this aspect...

Maybe things have changed - certainly when I looked at it a few years ago (around the time that google stopped supporting it) my understanding was that xmpp had no push notification support. The app in the phone had to either poll or explicitly hold open a TCP connection. (Which is problematic when the app is backgrounded.)

Has this been fixed in XMPP?

Yes, XMPP has had push notification support for years. It's the only way can work on mobile these days.

> It was invented before the iphone

That's true for email also. So that's not an evidence for anything lacking in xmpp. The plain fact is that Google killed it due to their greed.