C is in an odd position right now to argue it is how the machine is really working. Computers are more complicated since bigger caches entered the picture. Hell I do not think even ASM is a good approximation on how machine really work given the data dependencies will make stuff being processed in parallel instead of sequentially.

What you could argue is that C is the archetype for an imperative language procedural language with a clean mapping to ASM. That is different than how the machine works. Simpler architecture have less distance between their ASM and what is really hapenning.

C is still heavily abstracted. Modern OS evolved in conjunction with C s.t. it behaves like a C runtime simulating a PDP11 (I remember reading a nice article on that). To learn system, what you need is an OS course, not C. I'd say the current C-based stack is in a quite embarrassing state.