What if Google were the only company making Android phones?

Some of the common arguments I see against Android are that there are too many options for which device to get that and skins like Sense, TouchWiz and Motoblur aren't as clean or efficient as stock Android (I hear that one more after ICS was released).

Then I start wondering, what if Google were the only company making Android phones? They could make low, middle, and high-end phones and essentially guarantee that everything works the way it should. Updates would come faster and more regularly (I know it's often a carrier issue, but still), and build quality would be on par with current Nexus devices.

I'm not super familiar with numbers, but I'd assume that a lot of Google's revenue comes from third-party manufacturers like Samsung and HTC, so maybe this is a bad idea for them. However, I feel like we're at the point where enough people are familiar with Android that if they only had a few options and still preferred Android over iOS, they'd buy a Google phone anyway. I'd much prefer a world in which a Nexus lineup was the only one, because I think they're the best option if you're going to get an Android phone.

Be nice, please. :)