> still not widely adopted
Certainly everyone involved with WebRTC wishes that it had the support of IE and Safari, but Chrome + Firefox + Opera is nothing to sneeze at, particularly if you're targeting a savvy audience.
> Original two are not compatible
Maybe I'm confused, are you saying that Firefox and Chrome aren't compatible via WebRTC? I've used them together and had success, but just for basic video calling.
> not adopted in a single further browser in that time
This is fair, but if Microsoft's latest moves come to fruition that will be a big change. There are hints that Edge will likely support WebRTC[0], though I don't think there has been any official word. Maybe that's just for ORTC?
[0]:http://blogs.windows.com/msedgedev/2015/05/13/announcing-med...