Surely that calculation ignores the Block reward? The 25 bitcoin that is awarded to miners inflates the cost of mining equipment, by stimulating an arms race i

Surely that calculation ignores the Block reward? The 25 bitcoin that is awarded to miners inflates the cost of mining equipment, by stimulating an arms race in chip development. As the reward decreases over the years, there will be less incentive to pay a lot for mining hardware, and the overall cost in your calculation should decrease.