Covey was playing with a broken hand and had been a decoy for a few weeks at that time. Not to mention BYU playing UMASS and New Mexico State the previous two weeks before the Utah game and running very vanilla stuff in those games while they were prepping for Utah for 3 weeks. Whereas Utah was in do or die conference games leading up to the rivalry game and needed to win out for the South's top spot. Also, BYU could empty the tank against Utah and rest up for their bowl game. But not Utah, they had to play 6 days later in the PAC 12 Title Game.
Look, I agree injuries hurt BYU in that game. And BYU had Utah on the ropes. But there are factors or excuses that can cut both ways if we go down that road.