I think that the purpose of such a course is not to teach you a language. After all, Scheme, with its abstract syntax, is pretty minimal as a language. The purpose of a course like that is to teach you to think abstractly. If you can do that now, several years later, you can probably thank the course for getting you started. Abstraction, after all, is the big idea about computer languages.
A course in Python or another language can do similar things, but not in quite the same way, since in those languages you also need to learn the language syntax, idioms, and other structures. Scheme pushes all that aside for the opportunity to focus on abstraction. The things that are not in the language make it easier to focus on the big ideas.
This isn't really related to your question, but I note that many language designers start out with a lisp- (scheme-) like syntax to try out ideas in the language before they think very hard about its concrete syntax. It turns out to be very good for such experimentation.