just lack so much awareness about the complexities of 1) creating and teaching a defensive philosophy, 2) dealing with new schemes every week that are tailored to defeat that philosophy, 3) adjusting for injuries and other uncertainties, and 4) fitting all of those things into the ever-changing flow of a college football game.

But yeah, if only the defense got off the field sooner BYU would win every game.

Now, imagine if the defense got off the field sooner and gave the offense we had over the last 16 games
the ball more.
We would have been undefeated last year.
And the teams that were in the games late, would have been put away early.
Finally, I respectfully disagree with your assessment that the defense has won "many of those games." I would like to submit for your consideration that is was the offense that won most of the games. And, if they had the ball more, none last year would have been close.
Since no one has been able to stop the offense, take some more risks on defense, and get the offense the ball.