As developing software as a skill becomes like flipping burgers in a fast food company, is building hardware for evergreen industries like military and healthcare the only escape for actual engineers, not prompters?

Sure, it would be a lot more expensive to bring a product to market and sell, and more likely for a product to fail because of the long sale period. But at least you have a natural barrier then. You don't see some solo dev trying to compete with Apple in hardware, whereas in software nowadays there are billions of people who are your competition.