Google didn't really want to buy spectrum. Schmidt even publicly stated they had no intention to buy the spectrum. They were just after open access to the "C-block" of the spectrum which they got as a stipulation to them making a slightly higher than minimum bid. They got what they wanted, and it wasn't to own the spectrum.
With that said, I don't think google has any real interest in being a carrier, as that isn't where they make their money. They can leverage the mobile network much like the internet and continue to make their truck load of money via targeted ads.
With that said, I don't think google has any real interest in being a carrier, as that isn't where they make their money. They can leverage the mobile network much like the internet and continue to make their truck load of money via targeted ads.