Google is now a domain registrar. Given Google's history of making inexpensive things free, this doesn't bode well for current domain registrars.
On the other hand, Network Solutions is still the top domain regisrar even though it charges four times what GoDaddy does. It's probable that there's enough domain registrations to go around, but a free domain registration is a different proposition than a reduced-cost registration. The introduction of any cost to a transaction automatically limits the number of people and the removal of any cost tends to reduce the prices of competitors (and drive them out of business if they can't compete).
Google is definitely the company to watch in the Web world. It's the Southwest Airlines of the Internet.