I think you are a little low on the lease/rent costs too.
Here is what it costs to lease space at DEN
What is the rent structure?
The rent is equal to a Minimum Annual Guarantee (MAG) which is the rate per square foot or a Percentage Fee, whichever is greater. The Percentage Fee is established in the RFP document according to the concession policy.
Retail $70 per square foot
Food/Beverage $59 per square foot
Services $36 per square foot
Office Space $59 per square foot
Storage Space $12 per square foot
Obviously Denver wouldn't require a huge Skyclub, but let's use the relatively new club at IND as an example. It is 4,800 square feet.
There is probably a deal to be had on a large space, but even just renting storage space would run $57,600.