The legacies would have been profitable, too, if they flew their asess off like we do. Do you ever see a 20 min. turn at Delta or Northwest? Or see a Continental 737 board in just 15 minutes?
The legacies would have been profitable, too, if their business model and corporate culture was like ours. Have you ever seen a business passenger storm away and say he'll never set foot on a Southwest jet again?
The legacies would have been profitable, too, if they had one narrowbody fleet type and one widebody fleet type. Perhaps.
There are many factors for our profitability. Honing in on one is simplistic but fails to tell the whole picture.