Answer by Franklin Veaux:
When I managed a theater back in the 90s, we made no money at all on ticket sales. Not one cent. Every penny of ticket sales went to the distributor.
That means we actually lost money on people who bought a ticket but didn't buy concessions. All the money we made–all the money to pay for the building, pay employees, pay for the projection equipment and electricity, everything–had to come from the concession sales.