>Of course, writing in Lisp requires quite literally PhD-level understanding of algorithms and software design, just like a microkernel
That statement is absurd. I'd love to see a study on learnability of programming paradigms looking at new programmers with no prior experience.
My first programming course (less than ten years ago) used Scheme, which I found immediately understandable, intuitive, and simple to use. Then we went on to do a lot more work in imperative languages, which were a lot harder to get into, but coming back to functional programming everything now seems harder than when it was new because I can't stop myself from wanting to translate everything into a series of discrete steps to perform in order (simplification, but you get the idea).
I think my brain has been permanently damaged by prolonged exposure to imperative languages, but if I hadn't seen functional programming *first* I would never have known that.