They should. Let's think about it, Delta will recruit some Navy, then have their flows.
American Airlines will be only hiring a couple off the street for years to come.
United Airlines will hire you, but they're run by the special ed department of the American Industrial industry.
You can go to a virgin, Jetblue, spirit, but is that really what you want to do for a lifetime. If that's what you set out to be at, then good for you, but I believe most had much higher projections than a low cost carrier. Going to a low-cost carrier is not the next stepping stone to a major after a regional.
While Southwest is definitely not a company to complain about, progression and upgrades are stagnant for a long time.