I also must question the premise of this post. What benefit (if any) would there be if UA really pulled up their socks and improved meal service, on board amenities, crew friendliness, milage accrual, etc? Suppose also in this magical world that these improvements did not most the cost of the ticket by one penny. There's no doubt there would be a cost associated to all of those things but the benefit is unclear. At the end of the day most people will fly the airline that's the cheapest at the time, offers the best connections/routing options and/or is part of their company's contract. That being said, there are small things UA could do which would cost them nothing and would earn them kudos, namely providing more friendly on-board service and keeping their cabins clean!
-James