Google public dns is different than Gmail. It isn't the source of the data, for one thing. It's just a cache. The cost of switching to someone else's cache is a

Google public dns is different than Gmail. It isn't the source of the data, for one thing. It's just a cache. The cost of switching to someone else's cache is approximately zero. And it's not very difficult to set up your own nameserver that actually queries the root nameservers.