John Madden that I once heard (which I will paraphrase because I can't find it published anywhere). He said never retain a head coach or GM more than ten years because, no matter how good their intentions may be, they will inevitably grow too comfortable and stale. You see this with so many coaches, and I think there is a lot of truth to it.

At some point you need to look at the program and assess whether it is truly moving forward or whether it has become stale. It might be best for both the school and Bronco to move on to new phases in their development. Nothing against Bronco. He did an amazing job and probably belongs in the BYU HOF, but he's been around a long time and a change might be right for both.