I think special seasons are a bit random (injury-free, favored schedule, senior QB, outlier talent, etc.), but it makes sense that one ever once in awhile probably keeps fans happy even if the overall state of the program is in long-term equilibrium.
Also agree that 2006 was the closest we got to a special season under Bronco; so close on those two games. I have wondered if 2014 would have been one had Taysom/Jamaal stayed healthy the whole season.