I think you're reading a little too much into a preseason game. If it were the regular season, I'd agree with you 100%. The reason starters pour over playbook/film/photos during games is to try to identify patterns in the defense and what to do if faced with the same formation. In the preseason, its useless to study the defense because it's a base 4-3 or 3-4 defense without the blitz or coverage schemes.