Money is fungible but economics aren’t. If your CASM is too high because of fuel burn or maintenance costs or personnel costs or anything else, it’s still just too high. Plus, short haul routes have other problems. If I have to be at the airport two and a half hours before scheduled takeoff to park and go through security for a scheduled 150 mile trip, I can probably just take a bus and beat the time. Or AMTRAK in the northeast corridor.

And the arrival of fuel efficient narrow bodies capable of long haul will affect regionals too. With a 737 MAX 7 or an A220 or A320 NEO XR flying “thin” long routes point to point, hubs and regional feed may well be less important. The fact is that regionals exist because the legacies figured they could make money off them. That is less and less the case.