If they were defending against a HS QB then they probably wouldn't. It's a little more complicated when the guy can run like a RB, is fast like a WR, is big like a TE, and can throw like a QB. I don't care how simple the concept is, in the NFL you need film. If it were as simple as just hitting the QB every play, the option would be dead. You need to know tendencies and that's what film gives you. If you haven't researched your opponent, then all you're doing is reading and reacting rather than attacking. That's what the Packers did because the things Kaepernick was doing, wasn't on the film they watched. Jim Harbaugh and Roman played their hand well, Capers did the best he could do with the information and personnel he had.