Most of the top 100 players are not an option for BYU because they are not a good fit - they either don't like the school, don't like the honor code or won't fit into the culture at BYU and be and to deal with academics and other things. KY has said many years the top player won't be a fit at BYU, but he is now, so it makes sense to pay more for a generational talent that seems to fit within the BYU culture.
It might be sour grapes, but BYU is playing a different recruiting game than Self. A top player like Dybantsa is probably worth 2 of the other top 10 players because of how dominant he is. Basically what you get with AJ and say a top 100 kid will likely be better than taking 2 top 10 kids.