The "proprietary" OS features for accessibility are still ridiculously good and have only gotten better while Linux has been playing catch up.
Linux has not been playing catch up, Linux has been falling behind. Due to disability I use Sticky Keys and for a short time there was not a single supported distro in which Sticky Keys was usable. Now that it is usable again, it still has issues, such as if a modifier key is activated, a second keypress will not disable it even with the proper option enabled. I can work around this, but it is still a pain.