Had BYU taken the buyout for canceling the game, there would have been another home game in Provo. So, by agreeing to the Las Vegas game, BYU loses the home game profit. The payout from the Las Vegas game needs to be more than than the buyout amount plus the home game profit to break even.
So, how many people think Notre Dame was that generous to make the payout more than break even for BYU?