to fully accomplish such a feat? Think of what's involved in doing such. Acquire space, build, deal with FCC, manage infrastructure and service, etc. This would be similar to an auto manufacturer whose vehicles were developed to run best on a certain blend of fuel that they'd have to make and distribute by themselves. It's just a matter of money. How much would you be willing to pay for the tweak?
I was reading the iPhone OS 3 revisited and the idea hit me that things might be better if Apple was its own carrier. I think many would agree that the iPhone isn't as excellent as it could be because of AT&T.