Note that this is not incompatible with the author's view. The function abstraction does solve something: a problem we faced in the 20th century.

While I don't know whether I agree with their view, I do see that, once we've used the function abstraction to build a C compiler, and used this C compiler to build a proper OS, there is possibility for such an OS to provide entirely new abstractions, and to forego (almost) completely with functions.