Earlier quoted context omitted.
Sure. Much of the Google Talk video stuff was all designed for XMPP; they actively took part in the standardization at times. WhatsApp is XMPP, fundamentally, in any case.
Why is it not utilized more widely then? foregoing for a minute that everyone is cultivating their own gardens - what are the weaknesses of XMPP that would make it so easily avoidable for most of these apps?
1) the free protocols to do voice and video are not as good as the proprietary ones
2) it seems that every client use a different set of protocols for video and chat