Why should a coach get a bonus for reaching a bowl? It's their job.

Why should a coach get a bonus for graduating players? It's their job.

Why should customer service reps get bonuses if surveys come back positive? It's their job to be nice to the customer.

Why should sales guys get a bonus for making their number? It's their job...

You provide bonuses to Prioritize. For example, when Utah hadn't one an outright conference championship in football in like 50 years (even though McBride won three shared championships IIRC), Urban was brought in and got a hefty bonus for an OUTRIGHT championship because they wanted to make that a big priority. If I were at BYU I would provide the basketball coach with a nice bonus to win the WCC tourney since that has been particularly tough for BYU.

The bigger question is whether or not beating Utah is a higher priority than other games. I can't answer that, but if it is then you should offer a bonus for it.