Let’s start with the very reason why airports can charge exorbitant prices for garbage food: the very absence of the free market, caused mainly by a captive passenger market and government regulation.
Closed venues will always feature higher prices than open markets. On your way to work, you can choose between Starbucks, Dunkin Donuts, or even your local bodega to pick up a cup of coffee for a few dollars. Yet, if you’re at a concert venue, a place that you as a consumer have voluntarily chosen, the venue sets the prices because consumer demand is mostly elastic. Sure, you can pick up an 18-pack of Bud Light at a liquor store for less than a buck a beer, but a concert venue knows jacking up the price of a beer from $5 to $8 probably won’t dissuade you buying one during a show.