You are right to point that out, but I don't think the article is making a claim that its findings compose a recipe for exceptionalism. It actually seems very careful not to make any claims at all, except that it presents "a few of the patterns that have struck [the author] after having skimmed 42 biographies".

I do happen to agree with idle time, unrestricted access to information for self study and high level entourage.

Not so sure about tutoring.