Culture or lack of diversity at BYU. Players aren’t taking that big of a risk if they can always leave and not sit out a year.
BYU could be one of the biggest beneficiaries of the transfer portal for that reason alone.
Once players get to BYU, they learn that it’s a great place and many misconceptions are wrong and it’s rather a pleasant place. IE, Mormons aren’t racisit like the haters have been saying and it’s a great place to focus on school and athletics without the noise.