Heres the problems with 90 seat airplanes at the regional level...there are very few pilot groups who will hold the bar high enough on pay.

You have Mesa, Repubic, PSA all willing & fighting with each other to fly 70 and 90 seat airplanes for crappy pay. Hell, Co-Ex, Piedmont (if you break it down by seats), Airwilly, and a few others make more flying 50 seat airplanes than what those guys make for the bigger ones.

But the majors love it, if they can have the regionals fight over bigger airplanes for making WAY less than they should. . .then they're winning! I could care less if I'm flying a C152 if you're going to pay me what I expect to make for it.