Because when you start to win, recruiting gets much easier and good to great coaches will be successful at any level. If you have bad schemes and/or coaching, word gets around and recruiting suffers accordingly.
It was plainly obvious with the defense before Jay Hill was hired that the D scheme & philosophy were terrible. Unfortunately Arod while somewhat better probably just isn’t a very good OC relative to many of his peers. It’s also not good that a better QB & RB were not added this off-season. With a healthy LJ, BYU would have a much better shot at a bowl game however if his play time is limited, it’s obvious the offense will struggle.