For that to make sense Google would have to make a better Android. Plus Nokia "the company" are too much of control freaks, it would be like MS deciding to ditch IE and go with Chrome. Not happening, why on earth would they give up control and they are not running into bankruptcy?
The N8 with the dated symbian still a sell better than alot of other company's Android flagship phones, so it would be pointless. I also get the feeling, Nokia isn't in any rush to brake into the US market anytime soon since they are still #1 in the world.
If the Qt strategy works, everyone will be running to them not Google. Android is for the smaller players, not Nokia. Sorry Google.