Not to be argumentative, but I think there is more than correlation at work. It is just a theory at this point, and I recognize that even if you are a coach from the right side of the ball, you can still be a failure. Fore example, Charlie Weiss, Ty Willingham, Knute Rockne, and Ara Parseghian were all offensive coaches but Weiss and Willingham were failures. But Bryan Kelly is also an offensive coach, and seeing more success. So, you have to be the right kind of coach for the area that will provide your team a competitive advantage, but you still have to be a good coach. The failures seem to happen more often where the head coach's experience is on the wrong side of the ball from where it can get its biggest competitive advantage.
For Florida, it has tons of speed on both sides of the ball. Its biggest competitive advantage, in a league that focuses on defense, is to focus on the offensive side of the ball and take advantage of that speed. Hence, Spurrier and Meyer succeeded, and I predict Jim McElwain will as well. Alabama, in the same league, has never had the speed Florida has on offense. Its biggest competitive advantage is to have an overpowering defense. Hence, Bryant, Stallings, and Saban--successful defensive coaches. Mike Shula, an offensive coach, not so much.
Another example is USC. The PAC 12 is a high scoring offensive league. Because USC has talent on both sides of the ball, USC's biggest competitive advantage is a great defense stopping those high scoring offenses. Pete Carroll at USC--defensive coach. Lane Kiffen and Steve Sarkisian--offensive coaches. My prediction, Sark won't get it done because he isn't always going to be able to outscore other teams. Also, I think Utah will be successful in the long run with a defensive head coach, if they can get a half-way decent offense, because its competitive advantage is defense in a league where offense rules. :sick: They can't outscore other high-scoring offenses, so their biggest competitive advantage will be defense...and they have had very good defenses.
Think back to New Mexico under Rocky Long. It wasn't ever going to have a high-powered offense, but under Rocky Long and Bronco, they did pretty well with a good defense.
In sum, it comes down to looking at who you play and what you have. When I coached my son's basketball team a couple of years ago, I noticed during the player evaluations and before the draft that no one could make a basket outside of a few feet. So I drafted my team based on defense and rebounding, and focused mostly on defense and rebounding. When others did lay-up drills to warm up, we did rebounding and defense drills to warm up. We took second place in the league, even though I had never coached before, simply because I found out the competitive advantage necessary to win in that league and focused on that.
So, I don't think it is correlation without causation. I think teams naturally have a competitive advantage. Where they get their best talent, compared with what is needed to win in a league determines it. And when a head coach can emphasize that advantage, the team finds success.