Your software isn’t working, because the user cannot use it. Your UI is always a combination of whatever hardware and software come together to give an experience. Everyone chooses to marginalise certain segments of users’ technologies – I don’t support IE any more of course – but I typically won’t drop support for technologies that are vital assistive technologies for that segment of users.

(If you need a personal story to bring it home, the only way my dad, a programmer in the 70s-90s, could continue to use computers when he suffered from MND / ALS, was to use voice control software.)