I assure you its not. Try to have some vision.

If you are American Airlines, how would you preserve your regional flow?

You could:

1.) Mandate all new hires at American come through their regional feed, no exceptions including military.

2.) When the regional feed becomes as expensive as simply operating those aircraft in house, that's what you do, fly RJ's in house.

One has a large price tag. The other does not. Option 1 creates a new rung on the career ladder.