And I'm willing to bet a lot more that aircraft type has very little to do with what an airline charges for a given ticket. I suggest doing a little research on yield management.
Eh, don't think so either. Pretty sure the cost to move one seat a given distance is more expensive on a regional aircraft than a mainline one. Having large regional fleets have allowed airlines to sell frequency and flexibility, which thus far has proven easier to sell that one mainline flight at a lower cost into a given smaller destination.