Yes for instance if "Flea went to UC to learn music theory" it was to learn an advanced aspect of it and hang out in a college setting which he probly enjoyed. He grew up around theory, he was a competant HS trumpet player so he reads trebel cleff and has done hours of arpegios in every key (I know he studdied the Arban book, a dictionary of excercises) , knows fanfairs and orchestral parts by heart, soul and bigband ryhthm parts, and probably tries jazz improv. Importantly he knows when to forget it and make a groove and transition, but it's all Informed.
I once worked with a guitarist singer who had learned the whole John Fayhe book picking method, and she was good, her strat sounded harp-like, but as far as rhythm consistancy? Didn't exist, every time was different (except for the picking patterns, but they would be shorter or longer randomly, something she called "feel" which is actually e.s.p.) It was fun for a season, but too stressful to wonder a 'what will happen? feeling all the time. I don't mind outsider musicians as long as something about them is good.
(I'm calling them outsider musicians similar to Outsider Artists, these people who invent a techniqe never went to a school or sought the usual artist contacts. Maybe live in the woods.