actually you have it back wards , in my opinion.
mainlines are tied to the hub and spoke system, to much money invested in it.
mainlines wont have problem hiring pilots to replace those retiring, and they are many without any growth. the mainline hiring process at most has for lack of better term, a psychological test. This weeds out those who wont play ball with management, but mainline will still fill the cockpits. So mainline wont have any problems.
The problem is on the other side of there hub and spoke operation, the feeder side. Why not ask why they are so big on 12/4 pay caps, pay freezes, and 10 year term of contracts at the owned regionals. The non owned regionals since they wont have flow agreements to mainline will have to fight it out for what pilots are left, how are they going to do that, by offering pay cuts and reduction in benefits, i dont think so. Which one of the non owned feeders is even talking to there pilots about concession, none, just mainline owned regionals.
Thats because they want to get the owned regionals tied to a ten+ year contract with 1% raises and pay more for health insurance before the non owned regionals start negotiating. RAH management has stopped, EJT management has stopped and the rest have not started.

So it is not they dont need us, they want you to think that. for all i care they can bring all flying to mainline, but management will seek concessions from the mainline pilots there too.

As a foot note if my source is correct, to help out SKW, Delta has told management at SKW not to worry about the reset in there contract, why? Because that requires SKW to go out and seek concessions from it pilots and delta does not want any interruptions with there feed.

again that is my take.