There is no pressure to win at BYU.

If Kalani (or Bronco before him) felt that unless he delivered a BCS (when it existed) or NY6 bowl his job would be in jeopardy, there is no way they choose silly things like ability to give priesthood blessings or ability to deliver a great fireside talk or amount of grit OVER on field performance.

Look at the big time college programs where coaches make big dollars and with that money comes the expectation that they win and win now. If their QB is not performing sufficiently on the field, the next highly recruited D1 QB in line gets their chance to prove themselves. See Ohio State, Florida, Alabama, Florida State. All have made QB changes during the year when the day 1 starter didn't perform or was injured and the backup did better when given the chance.

Why wasn't a change made at halftime vs UCLA or Boise State? Why didn't the coach say: "look, you don't have it today, you sit next half"?
Because there is not a demand to win now and I don't think there has been at BYU.

The fact that BYU fans use reasons like those mentioned by OP is probably a big reason WHY there is not a demand to win at BYU.....