Earlier you mentioned morale. It's been low here for years but shouldn't have anything to do with jets being taken away. No plane is being taken away, and even if it were, the only thing that would change is our staffing/plane ratio would slightly improve. Your morale should have more to do with missing commutes and getting bombarded by calls from crew tracking every single day off followed up by performance/attendance emails from chief pilots right before going back to work your 98-hour, 11-day-off schedule at 5 in the morning.

Also you can't put 100 seats into a 76 seat aircraft. It doesn't physically work, even in an all-economy layout. Where do you get this stuff? Also scope.

United isn't about to start flying RJ's at mainline, either. Look up Scott Kirby. If they did, it would be a wonderful thing for the profession, but it's not happening any time soon. Endeavor is paying $50/hour to new hire FO's and $122/hour to topped out Captains to fly similar equipment. Apparently it's still economical for Delta, who incidentally has pay scales for CRJ900's starting at $86 and going up to $170. But even if the regionals had to start offering that much or more, Delta would still try to keep the flying at the regionals. Know why? Because after putting in your 2-15 years at a regional, you have to start all over at the bottom of the pay scale at mainline. If they brought RJ's in-house, you'd be moving up their longevity scale the entire time you're flying one. So no, United isn't about to start flying 175's in-house, even though it'd be better for all of us.