WebRTC currently relies upon a peer-to-peer connection for the video, i.e. between the browsers. Creating a meeting like the one illustrated with Webex above is just a total pain in the ass unless a central media gateway is used as a central video hub, which is not something WebRTC supports at the moment.
My kids are currently using snapchat to send messages to friends which include a single picture just taken with their smartphone. This, to me, looks a bit like videoconferencing with a framerate of seconds- or minutes-per-frame (think about it) so at the very least it suggests the real-time video isn't quite as important as the industry assumes. But, as mentioned, with the additional content it becomes more useful for remote collaboration.
Finally, HTML5 is capable of WebRTC video, plus all the various real-time chat, image/document sharing and multi-person annotation directly in the browser, so really that is where we should expect to see the most innovative development in this space, i.e. within the browser.