I think it's a little bit of all of the above. SWA has hired a lot (maybe too many) military guys in the last few decades. There is a very Air Force centric vibe here, which is good and bad in a lot of ways.
That being said, the balance is definitely shifting. There were four pure civilian pilots in my class out of 24, now many classes are over half. With a civ pilot, you get someone who is often 121 experienced with time in the left seat flying in a 121 environment. That pilot also doesn't have any reserve commitment and more than likely doesn't have another source of income to pad another reset to first year pay at another airline. You also get someone who has been to another airline and realizes that flying to Aruba does not require the level of attention that flying to Mars does.