Power usage is *everything* when it comes to ASIC. If you think it's not, you have no grasp on the economics of mining.
My simple math shows that
power usage is almost
irrelevant for an ASIC miner. Price per Ghash produced throughout the miners lifetime will almost certainly always be dominated by the initial investment, not power consumption.
Price per Ghash/s is the important factor.
Is my math wrong?
No, just your assumptions on difficulty. I don't expect any of these 60 GH range ASIC products to make even $1000 in 2013 alone. By design, difficulty will always bring the cost-to-mine very close to power costs. When it catches up, power costs will be all that matters. Until then, delivery dates before it adjusts are the key importance.
I didn't make any assumptions on difficulty. I fully agree with you there. Plugging it in first of all matters, but the gold rush will be over in a few days. Almost everyone buying ASIC miners will get them after the few first difficulty jumps, and probably after the block reward halving as well.
I do not agree that power costs matters as a competition factor between different current ASIC designs. All are going to be within the same order of magnitude. If it takes 25 years to spend as much on power for the product as you spent for the product itself, the price of the product is all that matters. In 25 years the next generation graphene ASICs will make the current ones compare to CPU mining in 2013.
Power costs is only a concern for miners using old technology. ASIC miners only have to worry about price per Ghash/s, because power costs will be negligible compared to their initial investment.