If the percentages hold true, then we should have seen about 10 BYU players drafted from these recruiting classes. I think that there's room to say that both arguments are true (BYU has a hard time getting talent AND Bronco doesn't develop NFL caliber players.)

Source of percentages: http://www.sbnation.com/college-football-recruiting/2014/5/12/5696710/nfl-draft-recruits-five-stars-two-stars

Source for recruiting rankings: http://byu.247sports.com/