That's just stupid. If Google wants to replace Verizon/ATT it will have fuck all to do with advertising. It will be for the revenue from users handing them a handful of cash every month.
Companies typically want to diversify how they make money, and this is very obviously something Google desperately wants given that pretty much all their new businesses are around NEW revenue streams and not advertising.
Perhaps Google want to diversify from advertising. Mobile communications would be one way of doing that.