Singhal is a Google product manager working on Hangouts. He confirms via Google+ — which I believe is a website Google employees use primarily to talk about Google? — that the plan is for Hangouts to absorb Google Voice, the way it’s already absorbing Google Talk.
However, he also says something about “better integration” which would imply Voice will stay around as its own product that’s just, y’know, integrated with Hangouts. So it’s not so much that Hangouts is absorbing Voice as that it’s absorbing Gmail’s chat feature, and its ability to make and receive phone calls.
Gee, would sure be great if the people at Google could finish making a crazy new plan before they start implementing parts of it. Maybe then they could explain what the hell is going on.