From what you wrote in Holistic Learning about the use of genius and innate talent to explain away successful learning, I think we agree that anyone without some relevant disability who is in a stable environment with access to the right resources should be able to do the same, and will after we learn how to teach how to learn. By "unimpressive," I mean "what one would expect, given what the wide distribution of mental skill levels and effort made by people who complete 4-year university says about its actual difficulty and the probable level of skill and effort of the 'productivity hacking' person doing it." You are comparatively impressive, and a very special snowflake.

Are you buying the textbooks/ finding your own? Just using the video lectures (and internet for removed sections) seems unbearably slow, and you aren't in nearly as much control over the flow of information.