I don't think the job markets are smaller nor does it take longer to take someone and teach them how to be a deveoper on low-level systems. These fields are more about knowladge and tricks to learn to make your software efficent and an understanding of existing systems. This is very easily codifiable in a code-camp like course.

You can take students and build real products (embeded systems like example medical gear and such) and teach them all of the same programming-specific information they already learn.

Now granted this wont happen any time soon. I don't think it's impossible I just think the kind of people who go to code boot camps aren't the kind of people who are interested in low level systems development. Maybe that's just a stereotype but as long as it persists people probably won't attempt to build things like schools like that.