I think someone [more prescient than me] previously suggested AS could maintain a non-EQD program, but still achieve some version of a sorta-EQD program. They have a variety of levers available to them, such as adjusting the required EQM for each level, modifying the EQM earned for each fare class and/or partner, increasing the metal requirement, etc. (Not to give them any ideas lol)

Certainly this is a [much] less precise way for a program to approximate EQD, and there may still be opportunities for individual members to qualify in a less costly way. But assuming a carrier usually looks at things in the aggregate, they may be less concerned with specific members qualifying too cheaply, and more concerned with something like, "how much is the average spend of each member at a certain tier, and how much is the average outlay for us for each of those members?" If the aggregate-numbers aren't to their liking, they can do something like broadly raise EQM requirements, and re-achieve their desired averages.