You can buy a Big Glup for $0.50 but it's $5.00 if you see it with the Matrix.
The theaters don't make their money from the movies (upwards of 90% go back to the distributor). They make their business on the concessions.
It's still only a nickel's worth of syrup regardless of what they price it at. Notice how they upsell popcorn and soda by offering free refills on the largest sizes only. It would seem that they are "giving away" more snacks this way cutting into profits but since the raw materials are dirt cheap, they win in this transaction.
Baseball teams make their money on the tickets, licensing deals, and concession contracts. The stadiums are publicly owned and while there may be a clause for maintainance, some team owners don't fullfill this part of the bargain.
Here in Houston, the owner of the team got the stadium rental for a nominal $1 fee and got additional revenue from renting the venue out for concerts.
I don't know of city owned movie theaters.