Sky, you may think that CAL and SWA are rare exceptions never to be duplicated in the future, but that is not entirely the case. Look at Delta and their retirement numbers. The have 600+ retirements PER YEAR projected to start a few years from now. That is 10% of the workforce retiring PER YEAR for a while. Who knows what will actually happen by then, but the point is, the potential is there. Always will be. And if it isn't Delta, it will be someone else.

Edit - the retirement at Delta peaks at around 500 per year not 600. But you see the point.