....could it be :
1. I, for one, eat before a game to avoid the crazy prices inside. Perhaps many others think the same way? Also, might people prefer to 'get their buzz on', before the game, and maybe only have to buy 1 or 2 of the 12 oz. beers for $15 each inside? I think this is logical. Leading to point number 2......
2. No money is made when people eat their own food, and drink their own beer outside before the game.
3. The longer folks have to "party" outside the stadium, many are already "three sheets to the wind" by the time they enter the game. Which may contribute to more altercations during the game.
That's me playing devil's advocate.... I agree, 4 hours is too short.