Google isn't going to get the spectrum! Kevin Martin (FCC Chairman) crafted the auction rules in such a way that it isn't attractive for Google or any other third party to bid, plus the incumbents have so much power in D.C. already.

Sure, they would like to build-out in the 700MHz band, but it is very unlikely to happen.

My guess is that Google never wanted to build a wireless network; instead they want a telco (who already has towers) to be tricked/forced to build a network that suits Google.