Also, there's a good question whether telcos will sell Google the ability to prioritize traffic, and then sell somebody else the ability to get out of that. The VPN provider will always be a minnow, so my guess is that if any of the whales object, the telcos will just never sign with the VPN provider.
With services like Facebook, Twitter, etc, the telcos know more or less what they can expect in average data usage from users (and plan/charge accordingly).
Therefore, a VPN provider will be in the same position. So instead of paying AT&T for your data plan, you're basically paying the VPN people for your data plan plus privacy from AT&T.