The change will have to come from the top meaning the major partner. They hold all the cards and are dealing them out from the bottom of the deck as they see fit. The regional world does not sell the majority of their seats and have very little control over their revenue, most just survive of scrappy contracts.
In what way this will happen I do not know. Ideally the mainline takes the jets with the crews. Will this happen? not likely because then the door has been opened and future contracts will increase the cost of having the jets on property. Then the carriers left operating with contracted feed will have a big advantage.