Got it,
I actually pay high or full fare most of the time. In fact, with a Y fare, I get either 1.25x or 1.5x credit times a 750 mile min per segment, which is a pretty good deal.
That was a pretty big point. Believe it or not, probably you are in the minority of most..... especially here on FT.
Probably the opinions of many of the people on this board, buy either cheaper fares if they have a choice, or purchase a mix of business when appropriate or low fares at other times, which would explain the strong sway towards AA. Delta's program probably competes fairly well for the few high or full fare flyers. I wish I worked for a company that didn't care how much of their money I spent for travel.
Have you also looked into some of the F fares or discount F fares. That may also change your opinion. Finally, it is possible that being loyal may really not make too much difference in your case.