The price of mining equipment is determined like almost everything in this world where the person and/or company selling a product looks to see what's the most amount they can get out of that product and then sets the price to make as much as possible. The cost of production is only used to make the decision as to whether to sale or not. Look at some basic marketing strategies if the previous statements didn't make sense.
Now how companies such as Bitmain sets the price of miners is a mystery, but my guess is do a simple future value calculation with some more complicated variables for BTC price, difficultly, reliability, etc. They will want to be sure you make a little bit of profit to ensure you return for the next model. Before making a purchase I recommend you make a similar calculation and determine if the difference (risk) between gain and break-even is enough to make a purchase worthwhile. There's a link to what I think is the best calculator above to determine this. As a cheat you can check the prices on eBay to see approximately the current FV. Auctions on there usually end a little bit higher than what I calculate.