Why can't I find anything on the day-to-day retail investing, that incorporates calc/linalg/DE, etc?

It's all highschool algebra and strictly linear approximation.
Surely if you're willing to put the wiggly stocks into a linear approximation, you could also cast it into a diff eq setting, control theory or something, and though it's also an approximation, it would give you a little more to work with?
Why's there such a gap between the retail investor "buy low sell high anything else you gotta have THE INTUITION" retards, and HFT nerds optimizing the physical distance of their lines to the market or pure theory math econ folks?