But there's the rub: comments aren't that valuable to anyone in the game but the commenters. No major YouTuber are moving off YouTube for a different uploader.

But there's the rub: comments aren't that valuable to anyone in the game but the commenters. No major YouTuber are moving off YouTube for a different uploader. Or even considering it. The biggest moves popular YouTubers have done are disabling comments. Google own the monetization of web video, so content providers won't leave. YouTube comments were already shit, so converting that shit into Google+ shit will at least help Google+. And if people disable comments, Google still get the views and gets to move the headache of dealing with YouTube comments to someone else (obviously if done in mass to a single discussion site this may be a problem for Google, but it is currently far too disjointed to matter much). From Google's perspective, the new comment system is a win-win situation.