The cost of a visa and a stay in North Korea is so low, and so few people visit each week that it wouldn't surprise me to learn that they make a loss on each visitor. It must cost them a lot to keep the hotel with 20 guests running, each visit site staffed, the 100,000 performers at the main stadium, the subway line etc. for 20-30 visitors a week. It is like a really large theme park with very few customers.