This was my takeaway from college. In HS, you don’t have a lot of prerequisites, excepting the “II” level classes. I quickly found out how unstable my math and physics foundations were. Luckily, few realize that Bs are closer to failing than they are to mastery.

Even the college gut courses have hidden dependencies. I still feel for the business majors in my entry level stats class when the prof, bragging about learning calculus at 10, required calculus proofs for all the things.

Much like Civilization and Diablo games, and @godber’s comment, those tech trees should be required for all course syllabuses.