three years now "There is NO substitute for experience.".
Obviously he's glad he got the opportunity, but he also had a very rude awakening just how unprepared he was with his lack of experience. Fortunately he is a special kind of person who had the ability to go through the pressure and come out the other side stronger rather than broken..a diamond in the rough if you will.
Good leaders set their people up for success and he likely doesn't want to put someone else in the position he was in unless absolutely necessary.
We should trust the judgment of someone who has walked through the fire and lived to tell the tale.