Almost none of them, but that doesn’t make them “places no one uses”, considering everyone who can see these words is looking at a device with a bunch of C firmware running on microcontrollers all over the place.
You're putting words in my mouth there - that's not my point.
My point is that if they're not running linux, and the ones that are aren't running a modern kernel, then we shouldn't hold back development of modern platforms for ones that refuse to keep up.