... to be assignment-sound on every play. The triple-option allows a team to have a relatively low yards-per-play, but because that yards-per-play comes with very low variance--i.e., triple option teams rarely have huge gains, but similarly they rarely have tackles for loss--the risk-return given the team's talent level is optimized. That's why when you watch Navy or Air Force, you'll notice they are content to average 3-4 yards per play playing disciplined football because that means they will be getting a first down most series.

At this point, BYU has neither the personnel nor the discipline to run triple option every once in a while.