I think that used to be true but that’s changed with all the advances in tech. Everyone has a tablet loaded with specialized video software developed for football. They all watch endless tape on teams they play and in doing so they see all the other teams they’ve played. I just saw something on Hard Knocks Indy (which is the best of the series btw) where Darius Leonard watched every run play the Pats ran all season to prep for them. He ended up watching 14 games worth of film just for one game.