When you account for all the other fixed and variables costs of the US Army, including weapon tests, I wonder what is the total cost of actually destroying a real world target. Must be easily above 50 M$.
With B-17 level bombing in WW2, you're looking at dropping 100 - 1,000 iron bombs to maybe accomplish the same thing.
Note the Stuka was a precision bomber, but required air superiority and good weather.