In the 80's and 90's kids from Utah weren't even looked at by big programs outside the state. Stanford, UW, USC, etc didn't bother much with the talent in Utah. And, as a result, they all ended up at BYU and Utah (in that order back then).

Granted, the state has grown significantly, so the recruiting pool is bigger, but the loss of recruits like these to non-Utah schools has had a meaningful impact on recruiting, particularly over the last 10 years. BYU would never get all of these, but back in the day, these recruits weren't even getting looked at by other schools, so their options were limited.

BYU may not go head to head with Utah for every LDS recruit, but if they go head to head with Utah on a couple, Stanford on a couple, UW on a couple, USC on a couple, UCLA on a couple, etc. it takes a toll.