Garretson was someone with half a season as THE starter and with a better record than Keaton. He also knew for 2 weeks he would be the starter as did the entire staff and so the game plan was right for the situation.
Nobody expected that week that Taysom would have an injury in that game.
You are obviously just trying to lie to yourself and others that the situations were remotely similar...let alone some how more favorable for BYU than USU...