How much of those parking lots do you think is dedicated to tailgating? (Hint: It’s a minor fraction of the overall surface lots).

Tailgating originates out of the lack of nearby bars, restaurants, public spaces around stadiums. That’s why there’s a trend of newly-built/in-planning stadiums in urban areas with entertainment districts attached. They’ve realized there’s money to be made, and creating walkable spaces just puuumps out the cash.