So would you teach your hypothetical son to quit every sport just because he didn't start?
I dunno about you, but I would support my hypothetical son to take full advantage of finding somewhere that he feels he can best make an impact. And if my hypothetical son feels his best chance to make an impact is playing QB in college football, and realizes that wouldn't be at the place he first chose to play and he subsequently decided to go elsewhere to make an impact, then good for him.
Simply put, if he was the "quitter" you asininely made him out to be, he wouldn't have been considered by the IU staff.