do they leave those schools early because of poor coaching, or do they leave for opportunities in the pro ranks? IMO coaches come here to be under McVay, coaches come here because he chooses those he works well with and have the same goals and agree with how to get to those goal. They leave as well for the same reasons as the college guys do for better ops, steps up the ladder.
I think you have a bitter pill with Sean and that's OK, but trying to find proof in the way you are doing doesn't pass mustard IMO. These coaches are not leaving because he's hard to deal with, or overly arrogant, or too demanding, or what ever you are trying to support. He hasn't "lost" any coaches...he has actually given them rise in acceptance among their peers.
College players go to schools with name, well thought of coaching because they hope to gain recognition while there and use that as a stepping stone to the pro game....So do the coaches who come to our team and go forward from there.