Just because computer science started with file systems and regexes (discrete math) doesn't mean that the systems of today or tomorow don't have very different foundations.
Thise are not abstractions over existing posix APIs or von neumann architectures, they are novel ways to do computation from a different branch of math.
Heck we don't even know if some of these are not breaking the church turing thesis by computing with true real numbers and not the computable subset that turing machines can handle.
Analog computers MIGHT.
It really depends on how quantized our universe is. If you have papers that show full quantization including tunneling probabilities e.t.c please share them! The physical existence of the reals has been a white whale of mine for some time ^^'.
I’m now wondering whether to consider both of these subjects foundational to CS or a CS degree. My gut says yes since so much relies on ML and AI is used a bunch (e.g. games and stuff).