Because with profits come pay raises or at least no paycut. The companies already set the RPM bar below that which they could make money due to market pressure from the LCC's. If they hadn't, SWA would be twice as big as it is today and you would be out of a job. Instead they turned their focus to cut costs to where they do make money; i.e. shrink capacity, cut employee pay, and new lease rates...etc.
Why so low? becuase what you see here today is not what this profession is going to look like very soon. We are actively creating global airlines to compete in and on the global scale. in ten years the sky team alliance will be known as sky team airlines. The LCC's will either be mergered into these global companies, be bought out, or they could cease operations, I don't know what they are going to do with them. However, your package is the global economy payscale, trust me, you are still making golden years salaries compared to what is going to be the average salary in the future. Unfortunately, right now the airlines happened to take it up the butt first. As such only the strong will survive the very difficult transition in the future of the airline business, since it is going to get worse than right now.