I would think at some point the 3 AA WO will be consolidated under one company (American Eagle?). The other three I am in agreement. I would add Horizon. Whether any are mainline, I have my doubts.

Consolidation from 20 ‘major’ regionals to 5. Only a few remaining specialty sweet shops, such as in Alaska and servicing EAS.

Instead of 20,000 pilots, about 10,000 pilots flying regionals. Most of the 50 seats parked (only places remaining are where it is nearly impossible to fill a couple of 76 seats in a day).

A lot of 76 seat flying replaced by mainlines flying 100+ seats. That does not mean reduction of pilots, rather moving a substantial chunk of regional pilot slots to mainline slots.