Why is there no pirate cellular?

Given the long history of amateur and pirate radio, why is it that there's no pirate cellular service? Theoretically, there should be hobbiests out there buying antennas and equipment and setting up their own little networks. I suppose it's more difficult than radio since you'd also need to build some sort of receiver, but again, you'd expect someone out there is doing this, if only on a small scale.

Am I missing something?