Most BYU fans care infinitely more about FB than BB. It's just a fact. What Duke does, frankly, is of no concern to me. Though I imagine they take the opposite approach, like at Kentucky or Kansas where FB is just a nice thing to pass the time until BB starts.
Even at the height of the Jimmer I still cared more about football. I would gladly lose every BB game or even drop the sport entirely if it somehow meant FB would perform better.