providing a student with a list of questions they got wrong and a good solutions manual ... works most of the time ... I'm capable of successfully working through entire textbooks' worth of material and needing no human feedback, which I'm told is not often the case

That's a very important point. My impression is that people can be divided into two general categories -- those who learn best by themselves; and those who learn best when being taught by someone.

I suspect that most people on LW prefer to inhale textbooks on their own. I also suspect that most people outside of LW prefer to have a teacher guide them.