I think this is unduly pessimistic. Take low-level kernel work, for instance. Between Linux, Microsoft, and Apple, there are lots of people who understand it.

I think this is unduly pessimistic. Take low-level kernel work, for instance. Between Linux, Microsoft, and Apple, there are lots of people who understand it. It's just a smaller proportion than used to understand it. The absolute number of people has probably grown. But we don't need every programmer to understand low-level kernel stuff, precisely because the kernel abstraction is good enough at hiding that stuff. Most of us don't need to care (whereas 40 years ago, many more did need to care). Personally, I myself never want to care about low-level kernel things. When I'm trying to write a program to do something, if I can write it without having to worry about low-level things, that's a win.