So you're saying there's a magical lock on the knowledge to reach mastery in any subject? Prove that magical lock to me.
I agree and I disagree.
Because of my work schedule I taught myself multivariate calculus, engineering physics II, and ordinary differential equations. I finished at the top of the class in all of these without ever attending class. These are hard topics according to most people, so it proves I have the ability to teach myself difficult subject matter.
However, with seven years of academic experience, I can say there are topics where the materials simply do not exist for one to teach ones self.
For example, last year I took an information theory course. Having to rely on a limited number of textbooks (that I could find), there is no way in hell I could have taught myself that subject without having the ability to ask an expert (i.e., my very experienced professor) and seek clarification.
Some areas in the STEM are simply too hard (given the materials
currently or easily available) to learn on your own.
This is the problem with advanced topics in STEM. More advanced topics (and even less advanced topics) are often extremely difficult with only a few experts in the world producing material on these subjects which means study material is very limited and any given study material will undoubtedly have holes.
Not to mention, when you teach yourself a difficult subject, often time you end up "over-learning". This is extremely inefficient.
When you take a class in college, you are assigned the important areas in the book to focus on. When you study yourself you must spend time on every area because you don't know what is important.
For example, I started studying switch mode power supply design using a very good textbook. If I studied this in college I could have done this in two semesters (16 weeks each). But as it is I have been studying for over a year now because I have to study every little thing to make sure I don't miss something important.
Would you trade a few thousand dollars to learn a subject in half the time?