Awesome defenses can dominate the Super Bowl. It's one of the most breathtaking events in all of sports. I still have no idea how anybody can call this year's version a dull game. We might not see that type of defensive dominance again for 15 or 20 years, unless the Seahawks do it again, which is unlikely. I'm not convinced that Goodell won't take steps to eliminate that type of defense.
BTW, it's actually unfair to the great defenses of all time to use 1989 Denver as an example. That's the team that is credited with a loss, in the #1 offense vs. #1 defense category. The '89 Broncos were hard trying and able to handle the weaker offenses very well. They had an impressive points per game allowed. But nobody was scared of that defense. Their raw yards per attempt allowed was very ordinary at 6.4, before adjustment due to interceptions. They allowed more than 20 points in both playoff games before the Super Bowl. Terrific defenses don't do that.
I was working at the Horseshoe sportsbook that year. We intentionally opened San Francisco higher than anyone else in town in the Super Bowl. We used -11.5 while others were at -10.5 or -11. We wanted Denver money. Within hours the famous gambler Billy Walters called the sportsbook office and berated us. He was a very good friend of owner Jack Binion and was working as sort of a sportsbook consultant. It was shady all the way. I've detailed some of it on this site previously, but not nearly all of it. Anyway, Billy insisted that we move the number down. He wanted us to be lower than anyone in town, not higher. He told us to change to -10. Billy asserted that, "the correct number on this game is 49ers -3." The sportsbook manager and I tried to restrain laughter. Luckily he stuck to his guns and we kept the -11.5 on the board.
Billy Walters was undaunted. The following day he showed up in person, again insisting that the number was too high. One criteria he used was Denver's defense, emphasizing that it was one of the all time best, and no way a defense of that caliber can get +11.5 points in the Super Bowl. I was newly in tune with yards per attempt in those years. I told Billy that 6.4 was unremarkable and that San Francisco with Montana and Rice at their peak were more than likely to chew up a pass defense allowing 6.4 yards per attempt. Heck, Bubby Brister had Pittsburgh 10 points clear of Denver at Mile High in the first half of Denver's opening playoff game.
As you can imagine, we had quite a bit of fun at Billy's expense in the sportsbook office as the score mounted in that Super Bowl. "Did he say 3 or 33?"