The F.C.C. gave up regulating C.B. radio when the sheer number of users made it impractical and unprofitable to bother with. It looks like drones are headed that way, too. There will be so many drones flying around that regulations will be ineffective, so the only thing that will allow them to function will be controlled chaos.
I suppose we'll need an interoperable protocol by which they keep from crashing into each other; that will largely be worked out by the for-profit companies using them to make money. Perhaps the F.A.A. can act as mediator, but they seem so far behind the curve on this as to be insignificant. The charge forward is underway already.