Earlier quoted context omitted.
If he's wrong and it's easy, why can no one do it? Why did Slack overrun IRC? XMPP left by the wayside by Google and Facebook? Because it isn't easy, and users will always value the experience over compatibility and principal.
Marketing, marketing, and amount of money that goes into that development. Give me a few thousand developers, a multi billion dollar ad budget, and the ability to signup every facebook user on the planet to my messaging service, and I'll also win against XMPP. In fact, with those resources carrier pidgeons would've won against XMPP.
Slack was a side project by a failing game company. Its growth was largely organic.
I think the original premise is right that user experience is more important than ethics or philosophy or whatever the heck it is we're talking about when federations come up