Which is where you're going wrong. You are correct that BYU doesn't have the individual talent that those teams possess, but the BYU defense as a whole seems to do just as well as those teams did on defense.

Now there is a case to be made that BYU played lesser competition than those teams, and therefore it's comparing apples and oranges, but then again, this years defense has new players and is being coached by bronco again, so comparing this years defense to last years defense is again apples to oranges.

I appreciate your sentiment, but it will do you no favors to discount BYU's defense. Their secondary doesn't have to be fantastic if they can pressure the QB. There is more than one way to skin a cat, as the saying goes.