Weird that Google isn't a founding member being that V8 is their creation. But I guess the reasoning is that Node isn't used internally at Google as they favor Go for server side code.
For other embedders, however, like TeaJS, SilkJS, v8-juice/cvv8, narwahlJS, this was probably their undoing, at least in my opinion. Stephen Beal considered it lack of documentation & support [1]. I have seen a concerted effort over the past 12 months to improve that.
[0] https://groups.google.com/forum/#!searchin/v8-users/support/...
[1] https://groups.google.com/d/msg/v8-users/MUq5WrC2kcE/Z3LyOmE...
That's consistent w/ what I've heard (whatever thats worth)
If you mean a JS replacement, they unveiled Dart in 2011 and it's not particularly popular.