A favorite game of sports fans, and one that Kobe has stirred up recently, is to imagine two dominant teams from different decades playing each other a conclude that one is better than the other. These debates are rarely about which team would actually win a game between the two, but rather which team is more significant or beloved by a particular group of fans. If these debates were actually just about who would win a game the answer would be easy: the more recent team (given enough time between the existence of the two teams) would win, no question.
Athletes get bigger, stronger, and faster every year, and coaches have seen and solved the strategic innovations that previous teams have used to gain a competitive edge over their opponents.
We accept this as fact in sports where there is an objective measure that allows for easy
comparisons over time. The Men's 100M sprint is one such event, and few if any fans, no matter how much they loved Carl Lewis, would suggest that he could beat Usain Bolt. We have the two best times for both men and Bolt's 9.57 is 3% faster than Lewis' 9.86 - no debate needed.
Baseball, basketball, and football have no such easy measuring stick. There are a fixed number of games that can be won and all performance statistics are produced by an offense against a defense, and the athletes and coaches on both sides are getting better. So instead we have endless debates on whether the 1985 Bears could beat the 2007 Patriots.
Some fans, having seen (and suffered through if you weren't a Bears fan) vividly remember how suffocating that defense was, how they could completely demoralize an opposing offense. Having seen such dominance, these fans will argue that no offense would stand a chance against it. By my stated rule above, however, I am clearly going to argue that the Bears would not stand a chance on the same field as the 2007 Patriots. As these types of debates have been going on since the beginning of sport ("Sure, this Sephes the Gladiator is pretty good, but did you ever see Spartacus, now he was a gladiator.") I am not going to be able to prove this to you beyond a shadow of a doubt, but I will offer some evidence.
Let us begin with remembering that dominating defensive line of the '85 Bears: Hampton, McMichael, Perry, and Dent were all outstanding players that season, and as a group, they averaged 281 pounds. The offensive line, while not as celebrated, included some very good players, and had an average weight of 274 pounds. Now weight is not by itself a determining factor in line play, but it certainly helps, and those lines were not small by the standards of 1985. The 2007 Patriots however, as the table below shows, were much bigger. The Pats offensive line averaged 306.4 pounds (11% more than the Bears O-line) and the Pats defensive line (even including Adalius Thomas a Linebacker who was at times a defensive end) had an average weight of 296.3 (5% heavier than the Bears D-line).
The size advantage for the Patriots on the offensive line is one indicator of why the Pats would win a game played between the two dominant teams, but it does demonstrate that athletes get bigger, stronger, and faster, and the 1985 Bears would simply not be able to manhandle the 2007 Patriots the way they did the 1985 Patriots.
The important issue for fans though is just because the 2007 Patriots would win the game, does not diminish the 1985 Bears anymore than Bolt's impressive times diminish Carl Lewis' amazing performances. The '85 Bears defense will always be one of the great defenses in the history of the league, it just would not be able to handle the offenses after 20 years of athletic and strategic evolution.