You're missing the point. It's not that we should all get down to the lowest common denominator, it's about having useless visual bling (that is annoying and distracting even for a healthy person) that serves no useful purpose and CAN'T BE SWITCHED off making the phone unusable for people with a medical condition.
Again, the solution is not to force everyone to use a static UI, it's to give people the choice. Which is something Apple never does, I guess because then there would be people who switch it off and then complain that it does not work. I am an iPhone 5 user recently switched from Android and while the phone works just fine, I sorely miss the ability to actually customise anything.