I know JUCE is all about being cross-platform, but a possible answer is to just support accessibility features on macOS/iOS since from what I understand they’re lightyears ahead of what Windows/Linux can do.
This would eliminate the need for feature parity/lowest common denominator implementation. Additionally, as has been said Apple actually cares about accessibility in their products so I would guess a majority of disabled users (especially disabled musicians) would benefit from this (since a sizable population of them use Apple products due to their better support).
The pushback on adding any sort of accessibility to JUCE, even basics like screen reading, is understandable from a short-term pure business standpoint (not having to put in the effort) but really disappointing none the less.