Several hypotheses occur to me, all of which are probably true to some extent.
First, a teacher working in official capacity can’t give useful cynical advice on how to game the system. A private tutor has no such constraints.
Second, top-rate minds rarely, if ever go for careers in full-time teaching. They might become university professors who like to do some teaching as part-time work alongside research (and perhaps entrepreneurship), but definitely not full-time teachers. Geniuses want far greater intellectual challenges, and they want to climb much higher peaks of accomplishment, status, power, and money. So if you want great minds to teach you, their time will be available only on a part-time basis and for a very steep price.
Third, in my experience, one-on-one conversations with someone knowledgeable are far more efficient than group classes for learning complex technical and math-heavy subjects. Lectures are great for learning about soft topics like e.g. history, but in subjects that deal with some complicated and non-intuitive formalism, the lecturer will inevitably be slow and boring for some students and too fast and unclear for others, so the average worth of the lecture per student has a pretty low upper bound, no matter how good the lecturer might be. In contrast, a highly skilled private tutor can figure out exactly what the student needs and make far better use of the same time, so I don’t think it’s irrational to value top-grade private tutoring far more than top-grade group classes.
Several hypotheses occur to me, all of which are probably true to some extent.
First, a teacher working in official capacity can’t give useful cynical advice on how to game the system. A private tutor has no such constraints.
Second, top-rate minds rarely, if ever go for careers in full-time teaching. They might become university professors who like to do some teaching as part-time work alongside research (and perhaps entrepreneurship), but definitely not full-time teachers. Geniuses want far greater intellectual challenges, and they want to climb much higher peaks of accomplishment, status, power, and money. So if you want great minds to teach you, their time will be available only on a part-time basis and for a very steep price.
Third, in my experience, one-on-one conversations with someone knowledgeable are far more efficient than group classes for learning complex technical and math-heavy subjects. Lectures are great for learning about soft topics like e.g. history, but in subjects that deal with some complicated and non-intuitive formalism, the lecturer will inevitably be slow and boring for some students and too fast and unclear for others, so the average worth of the lecture per student has a pretty low upper bound, no matter how good the lecturer might be. In contrast, a highly skilled private tutor can figure out exactly what the student needs and make far better use of the same time, so I don’t think it’s irrational to value top-grade private tutoring far more than top-grade group classes.