It benefits nothing to let ND buy their way out of the game (which would likely be somewhere around $1M) so that BYU can replace them with some G5 team (and either schedule a H/H with them or pay them $500,000+ for a money game) that will be televised on ESPN3.
(*from 2008-2015, the average per-team payout for the Chick-Fil-A and Cowboy Classic neutral-site games was around $2.6M per team).