What are the reasons that none of the full-service airlines positioned itself and delivers as a high service quality provider?

Why do you think U.S. full-service airlines are largely undifferentiated, low-quality providers?
What are the reasons that none of the full-service airlines positioned itself and delivers as a high service quality provider?
How might people feel if they are working in a culture that focuses so intensely on customers, but cuts costs to the bone internally?