He did make his offense functional. But by the time they took a 20 point lead, the net yards for both teams were nearly equal. At that point it was a field position and special teams game. Which he was also winning.
Which is simply a long way of saying, he doesn't work miracles, but he doesn't leave any stone unturned either. He went through a long stretch where he could not draft to rebuild his D, but he has fixed that in the last couple of years. Its no mistake they got another Lombardi after that happened.