Money. I guarantee BYU could get more money if they shopped around. The thing is, nobody likes CBS Sports. Fox/FS1 is getting better and may be ready to compete toe to toe soon but right now if you want eyeballs, you want to be on ESPN (or ABC) and that is what BYU wants. I would bet BYU would prefer BYUtv to ESPN+ (meaning they would probably take less money to be able to simulcast the game).