What I took away from OP's story is that his friend "R" was a more useful source of lasting wisdom than his MIT instructors. Why? Because "R" had cultivated an air of confidence, charisma, and credibility. How "R" achieved this wisdom himself is a red herring.
P.S. This also isn't about my gripes with academia. I have no problem with people squandering their time and money and lives on any variety of "rat race", including the various diversions that people consider to be an education. As I said, you have to "taste" for yourself to truly understand. I have no agenda to change anyone's mind with words. I was just sharing my own revelation about the OP's message.
Allow me to further muddy the waters with another Nasrudin parable:
An opinionated and small-minded cleric was lecturing the people in the teahouse where Nasrudin spent so much of his time.
As the hours went by, Nasrudin realized how this man’s thoughts were running in patterns, how he was a victim of vanity and pride, how minor points of unrealistic intellectualism for its own sake were magnified by him and applied to every situation.
Subject after subject was discussed, and every time the intellectual cited books and precedents, false analogies and extraordinary presumptions without intuitive reality.
At length he produced a book which he had written, and Nasrudin stretched his hand forth to see it, because he was the only literate man present.
Holding it in front of his eyes, Nasrudin turned page after page, while the assembly looked on. After several minutes the itinerant cleric began to fidget. Then he could not contain himself any longer. ‘You are holding my book upside down!’ he screamed.
‘I know,’ said Nasrudin, ‘Since it is one of the archetypes which seems to have produced you, it seems to be the only sensible thing to do, if one is to learn from it.’
(With credit to Idries Shah, Octagon Press)
A con man also cultivates confidence, charisma and credibility. That doesn't make him a source of lasting wisdom.
In any case, if you admire someone as a mentor, why would their path to success be a red herring? Wouldn't you naturally be curious about how they got where they are?