They don't need to cover all disabilities, that's ridiculous. Kinds, severities, and combinations of disabilities are endless. We make a reasonable effort that importantly must make sense for the application.

The person you've constructed in this scenario is both blind and deaf. Such an unattended person is in extreme danger on streets with automobile traffic no matter what the crosswalk button does.

No, the person I constructed is only deaf. They attempt to touch a button and do not realize that button did not register their attempt.

I agree that not all disabilities can be accounted for. However the more we account for the better - where accounting is all aspects of getting around. I don't know how to make it safe for a blind and deaf person to navigate streets safely - but I wish it was possible and as soon as I learn of something that works I'll support it.

If they're only deaf, then it's asked and answered because these new buttons have LED indicators and the sound they make can be felt through the housing. The ones near me might as well be knocking.

A guide dog is literally trained for this.

At some point, a disability requires assistance. That is less true these days than in the past but still a last option.

There is a simple solution for making these buttons accessible for all, and we have them in the UK.

It’s a simple button that clicks, and under the panel there’s a small knob that rotates. Click the button, then place your fingers on the knob and wait for it to start spinning. I can’t tell you if the crossing call button is completely broken (although you’ll figure that out if wait long enough), but broken call buttons in the UK are pretty rare, I’ve only encountered a small handful of broken buttons over 20 years.