You are right though that there is a small number for straight D1. But the D2 competition is very good from schools like Lewis and McKendree, both of whom are ahead of BYU in the current NCAA RPI.
It’s a shame that the fastest growing boys sport in America, volleyball, is about to get kneecapped at the D1 level by the House settlement.
It’s growing like crazy at D3 and even D2 levels. But D1 will probably never grow.