In the past, people would buy season tickets because BYU was on the schedule. It helped ticket sales in a lot of ways. Currently, Utah is selling out their season ticket allotments far before the season even starts. People don't care if they have to go to 2 easy games if it means they get 5 quality home games on top of that. If Utah plays BYU every year, they give up a home game every other year. That right there is bad for business. And the replacement game will still sell out or come very close to selling out, meaning that the money lost is trivial. Their TV revenue won't change from ratings from the Y game. The more I think about it, the more I realize that this game just doesn't mean the same to Utah financially as it used to. In fact, it's not even close.
