Maybe I’m misreading my interactions with young folk, but I think there are a lot of talented athletes that were born and raised in Utah that see athletics as their ticket out of the Utah bubble. Couple that with the current structures that exist within the NCAA (CFP, conferences, etc) and the allure of non-Utah schools make sense.
All that said, I agree that if BYU were to dominate in-state recruiting, they’d have a lot of successful programs in a lot of different sports.