"They are killing Jingle and XMPP by depreciating Talk..."

As of two or three weeks ago, the Hangouts videoconferencing code used WebRTC, Jingle, and a variety of video and audio codecs (among which one could find Opus.).

If you run the software on a *nix system, you can verify my claims by checking the contents of /tmp/gtalkplugin.log while you're in a video call with someone. Note that that file seems to be flushed to disk at irregular intervals, and that it is removed after the call is terminated.