Disney was an industry leader in accommodating the disabled long before the ADA was enacted in 1990. It often goes over and above what is necessary without being forced to do so at gunpoint.
The ADA requires only reasonable accommodation, and what that means will differ with the circumstances. Disney used to give out GAC cards, which allowed front of the line access. When too many people asked for them, it switched to the DAS program, which is not as good. Disney was sued, and they won - apparently, the GAC access they were giving was more than they were required to do. If people abuse the current system, I guess we'll find out how little Disney can do and still be doing "something."
The aspect of the ADA that is most controversial is the provision that does not allow inquiry into, or require proof of, disability. That provision is not required by some higher power - it is not an immutable law that must forever remain. It is a provision that was adopted by our legislature and it can be changed the same way. It's already being challenged in court by businesses due to people bringing their family pets wherever they like by representing they are "service animals." If this gets out of hand, my prediction is that the ADA will be changed to require some sort of proof.
People abusing the system will eventually result in those who are truly disabled getting less. It has already happened when Disney changed from GAC to DAS.