The NFL is a business and to that end it is designed to make money. Since the Pats have the highest ticket prices, and are selling out, the league has to continue to support them to keep the revenue stream. Revenue sharing is what causes this issue. Buffalo selling out a game is not nearly as lucrative to the league as the Patriots selling out their games. If the Pats start to lose, then the fans do not show up and too much money is lost.