Issac,
Your definition is one dimensional. There are multiple facets you are not considering, least of which is do all planes fly 100% full and would current elites fly if the rules are changed. From my experience most flights are not full and I would not fly if the rules make it too expensive to fly for elite status. Perhaps you should go back and think beyond x + y = most value customer. This is a multivariate problem and AS has determined yields the best net revenue stream. Go back and think of all the variables and then see if your initial conclusion is correct. I think you will come to a different conclusion.
It is also the reason AS has chosen not to accommodate more than 2 on a reservation of upgrades. Multiple factors are at odds and different valuations of the factors are in play.