I think Tanner Mangum is a decent example of BYUs coaches recognizing that the possibility of losing Taysom to injury was higher than usual. Yes, part of it is his talent, but clearly they made it an emphasis to help Tanner be ready if and when he was called upon.

Also, you are right that injuries happen, but not always to your star players at key positions. You are right that BYU would benefit from greater depth. Bronco has said so himself. Part of that is a challenge with recruiting, part of it is a challenge from missions, and part of it is probably areas that the coaches can continue to improve, but to blame it all on Bronco is short-sighted.