When most people had no or very little education, and some people had access to private tutors is it surprise some of them end up exceptional?
I mean you are talking about pre internet era and era where people were relatively less knowledgeable.
Today private tutoring still gives edge anyways. As you can personalize the needs of pupils.
I cannot imagine someone having several private tutors since childhood and not being exceptional in some regard or above average at least in knowledge if not intellect.
Science is blind.