I agree with your points. This defense really just sets the offense up to have the pressure to win or lose games.
It is very difficult to come from behind while defensively giving up long, sustained drives, even if they end with field goals instead of touchdowns. Both from a consuming-time aspect and a momentum and emotion aspect.
BYU had not trailed at all this year before Saturday. Unfortunately, the combination of fumbles and offensive ineptitude in the rain pulled Boise into the lead and gave them the momentum. The defensive scheme does little in a situation like that to gain back the momentum or help the offense come from behind.