I don't think you understand how that works.
I used to work in TV and used to be a network switcher.
All commercial breaks, whether local or network or scheduled with promos at the end for a reason.
That way if they have to clip it because they are running late, etc. they won't have to clip a paying spot.
Any paying spot that gets clipped or goes wrong for some reason gets a makeup spot either that day or later. It's in the contract.
Next time you watch TV notice that a promo is always the last thing you see before they go back to the programming.
I'm sure they had no problem selling out their commercial spots, the Super Bowl is watched worldwide not just nationally.