...I think the NFL has sort of a mindset with the average BYU player and that mindset is they aren't highly sought after by other NFL teams and so why waste a draft pick on them when you can probably sign them as a UFA after the draft. Save the draft pick for a player from a p5 school (like a USC, Bama, etc) or for an under the radar kid that has potential.
Exceptions aside (Ansah, KVN), I think the NFL has BYU pretty much cast in stone.