That's been discussed heavily elsewhere. I think for a place like France, where in any given region the percentage of cyclists on tour (from elsewhere) is probably greater than 50%, it could make a lot of sense. I envision a place like Decathlon Sports, which has a ton of stores (and open reasonable hours, something relatively unknown in France), having a setup where you could rent a bike in one place, return it elsewhere.

But for now, such a system doesn't exist.