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.
Google is working in coordination with io.js and have expressed that they believe it is the future. They're moved their integration and effort from Node to io.
At least from what I've seen publicly on v8-users list, that is not true. Google has not, and seemingly, will not pick a side. Or, if you must, they've picked Chrome/Chromium and its 6-week version/development cycle. The v8 team has always been clear on this. Their primary (only?) customer for v8 is Chrome.
Here's an example [0] where Googles showed they preferred their ICU implementation over system, in effect, remaining self-sufficient & neutral of the embedder's concern. And as an independent embedder with a non-public project (as of yet), I prefer that neutrality.
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.