Ben Hogan?
How many lessons did Ben Hogan give?
His book (like so many done by players) tells how a golf swing should be based on how his (Hogan's in this case) swing feels. Case in point, if Hogan turned his hips to the left during his forward swing like he writes in his book...he would have never made this list. Because no one would have cared what he had to say because he would have been a mediocre player at best.
Likewise, Nicklaus always talked about talking the club straight back and square to the line as long as possible. But his clubface was a little shut for the most part in his backswing. He worked it open in his downswing to produce a fade...like so many others do(e.g. Stadler, K.Green, Azinger). Though it was shut, he didn't feel it to be shut, and so he wrote that it was square.
Having Hogan on this list is like having Micheangelo on a list of greatest art teachers.
Teaching is getting the most out of your students, no matter the subject, and no matter the student. It is not simply being great at something and telling others how you did it. That's more akin to preaching.
BTW, to not have Claude Harmon on this list is a travesty. He could be found on the lesson tee, and often...teaching not only his assistants to be better players (see Dave Marr), his sons to be better players (Butch was on tour for a few years), but club members of all abilities.
And he survived a coup attempt on the King of Morocco while teaching him!