Blve it was Gordon Bethune of CO who said if your focus is to drive cost out of your business, at some point there will be no cheese left on the pizza.
I used to work for said company when they were competing with BA on UK domestics and saw Diamond Service successfully introduced. Premise was frequency and service, especially service. If they lose the key differentiator from their competitors (as well as price) then they will truly lose their market position. This is marketing 101. By the way, whatever happened to the famous breakfast ?? (BMI can't be as bad as Delta though - can it??).