LOL where did you get that number? If you're basing it on BFL's ASICS', just remember that:
A) They have not released their product yet.
B) The hashing power will grow infinitely, and anyone is free to buy their own ASICs too.
the production cost of an asic is only a few dollars. It is true, that anyone is free to buy one, but what that means is if you buy $X worth of BTC, you should also invest comparable amount in the mining equipment, to make it secure.
The production cost of the chip is only a few dollars, add in the circuitry and assembly and you up to tens of dollars.