Which is interesting because I use a dialysis machine and these are essentially sold to the government instead of the patient yet they all use a custom GUI interface like this one. Far as I can tell there is no accessibility features.

That's a difficult case, because it's a dedicated device and not a general-purpose computer. Adding a screen reader to such a device could be costly. Of course, these days, even a lot of "embedded" projects use Linux, some embedded flavor of Windows (previously CE, now Windows IoT Core), or even Android. Still, the device would need audio output. And to really cover the bases, for deaf-blind people, it would need to connect to a braille device via USB or Bluetooth.

In my ideal world, all user interfaces would run on the user's main portable computer (currently a smartphone), controlling devices remotely over Bluetooth, NFC, or the like. Embedded UIs would then be a thing of the past, and accessibility would simply be a matter of following the recommended practices for mainstream general-purpose platforms.

TBH this looks mainly oriented towards games where usually the only UI accessibility you have to be concerned about is for people with color blindness.

It's the only accessibility developers usually ARE concerned about, but in many games, it would be possible to do much better. Uncharted 4, for instance, is highly accessible: https://dagersystem.com/all-review-list/disability-review-un...