Delta doesn't pay regional wages. They pay a regional airline a fee for every departure. It's a fixed price, hence the low pay required for regionals to make a profit. They undercut each other to get the contract, then cut every corner to turn a profit on that fixed price.

Delta has come to the realization that replacing 5-7 RJ flights that are unreliable and hated by customers, with 2-3 full 717's is much more reliable and profitable. United is right behind, we're flying 737s and 320's into more and more places that were RJ legs, just with less frequency. We've also announced we're cutting 50 seat RJ capacity by almost 50%.