It is in football. It’s a simple matter of numbers and demographics. BYU will always be able to recruit enough size and shooting to be good to very good in basketball. If it can augment its traditional recruiting with a few non-Mormon athletes, it can be excellent.
The church simply doesn’t produce enough top shelf D-1 talent for BYU to be consistently great at football. Especially given that most LDS blue chippers are signing with P5 schools, and given the current landscape of college football.