If I had to take one defense of all-time as far as dominating an entire season including the postseason and Super Bowl, I would take the 85 Chicago Bears with their 46 defense. That Bears team doesn’t win the Super Bowl without Mike Ditka. A big reason why Buddy Ryan didn’t win a Super Bowl or even a playoff game in Philadelphia or Phoenix, because he wasn’t as good of a head coach as Iron Mike. Buddy could get his teams to the playoffs and even win a division, but he was a defensive oriented head coach, who didn’t have much respect for offenses, even his own. Mike Ditka was a complete head coach, who was offensive minded, but understood both sides of the ball very well. And knew he also had a to have a good defense to win championships.
But I believe Buddy Ryan’s Eagles were better on defense of a longer stretch. From 1988-91 and 91 was the Eagles first season without Buddy, the Eagles might of had the best defenses ever. Buddy might of of had more talent on defense in Philadelphia, than in Chicago. And he certainly had better teams on offense, even though he never had that one running back he could count on to lead their running game. One of the reasons why he wasn’t successful in turning the Eagles into a Super Bowl contender was that he ever really even had a good running game. A good passing game with good receivers like Fred Barnett, Calvin Williams, Keith Jackson, Keith Byers out of the backfield. When Randall Cunningham was on, he was about as good as any QB in the game.
Imagine how good those Eagle teams of the late 1980s and early 1990s would have been had Mike Ditka been their head coach and not Buddy Ryan. Ditka would’ve given the Eagles a running game and known how to work with Randall. And then you have either Jeff Fisher or even Buddy running the defense. They Eagles probably would’ve probably already have their first Super Bowl championship already. (sorry Eagle fans) Buddy I believe had better defenses in Philadelphia if you look at their secondary and then you have Reggie White on one side on the d-line, and Jerome Brown in the middle, who were both almost unblockable. And then Clyde Simmons on the other side of Reggie. And the Eagles had more talent on offense, but Buddy wasn’t a good enough head coach as far as both sides of the ball to take the Eagles to the promise land.