If regional airlines can't fulfill their contracts due to staffing issues they will eventually shrink as mainline 717's and 319's pick up the slack. Management and mainline pilot groups don't want to even entertain the headache that an integration would entail. And yes, mainline airlines are very selective about who they hire and don't want to give up that control.

It will never happen.

However, if you keep your nose clean and network, the majority of regional pilots will be employed by majors within the next 10 years -- they'll just have to accomplish this the traditional way (heaven forbid.) Except for the "page is shame'ers" who "Don't want to commute to NYC to sit reserve." (Yeah, that's what's holding you back.)