The reason the regionals get paid so bad is first there are pilots that are willing to work at bottom feeder regionals. If they couldn't hire anyone they would have to raise pay. Second is the big three trying to get the cheapest labor they can and being greedy and extending "regional" flying, now over 40% of the big 3's product is delivered by regional pilots getting paid 30% of what the major pilots make.
With this huge discrepancy in pay it has caused pilots now to move to intermediate companies like the ULCC's which are now cutting into the big 3's market share and they are scrambling to find a way to compete. They kind of shot themselves in the foot on that one. Who knows how much market share the ULCC's will ultimately get or if it happens overseas to the likes of NAI and possibly others. Nobody thought Southwest would capture much market share and looked how that turned out. Now it's Cheap gas, airplane orders, pilots willing to work for less pay (more than their regional) and the sky is the limit.