Actually, mainline pilots could take it all back in less than a week. All they have to do is grind the airline to a halt until management puts the planes back on the list. Management is NOT going to fold the airline over scope issues, at worst they will park the 50-76 seat jets and not fly them.
The problem with scope recapture is a numbers game. Take for example DAL if you put the 7000+ DCI pilots back on the list, they are going to want mainline pay. Money doesn't grow on trees, that money has to come from somewhere, and that's out of the senior pilot's paycheck.
FACT: This industry is exactly the way pilots want it, they show up to work, and vote yes on these substandard contracts. Most of NWA concessions were given back voluntarily before the bankruptcy of 2005.
You can say you're taking it back till you're blue in the face, it isn't going to change anything unless ACTION is taken.