I see what you're saying, but all plants respond to things differently. I have Spider Plants in my house that I couldn't feed 1200PPM of nutrient solution every week, but cannabis could be fed that. Every plant is different, so as far as cutting folklore down, it probably wouldn't do much. As a botany major, I'd say they would probably teach you a lot about the very general biological functions for all plants, and not get too specific into one genus/species/phylum (I forget which one). And they especially wouldn't tell you about how to grow cannabis, which is all that really matters on this forum. Hell, I'd say a lot of the standard operating procedure that we all do for our plants was folklore at one time, then eventually someone had a hypothesis, tested it, proved it, and then products and techniques were created from there. It all starts with an idea, hence why most everyone on this board will tell you that the best way to learn is to start doing it, experiment with it, try some new things, and most of all, have fun.
EDIT: That made it sound like I am a botany major, I am not... I just phrased it weird.