You're completely right. Although Messi's manager was his father but he was the one that makes Messi have a change of heart when he decided to move to Man United due to the problematic false allegation said about him by the club board despite all his commitment to the club.
Obviously the father decides for the sake of the son, what better manager one can hope to have.
Sometimes money is not everything, having money and being hated by all your fans is not a good thing.. and when you are already rich, these things matter.