I’m just trying to think about what might be done to preserve it in its most helpful form for as many people need it.
Disney doesn't need you to think about this. They have people who do this for them.
Disney has the data they need and they have made tweaks to the system that have made it MORE user friendly since its inception, so it stands to reason that they don't feel they need to change anything about how people qualify for one. If they get different data as time goes on, they will change how the system works.
The threat of a lifetime ban for lying to obtain a DAS is probably a pretty good deterrent.