yes, this is an oft-reversed causation. The price of bitcoin is determined by the same thing the price of everything is determined by in a market system. What t

yes, this is an oft-reversed causation. The price of bitcoin is determined by the same thing the price of everything is determined by in a market system. What the current supply of bitcoins is and what the current demand for those bitcoins is. The "cost" of mining doesn't even enter into the picture. How mining does enter into the picture is the ingenious way that difficulty auto-corrects. If bitcoin prices plummet and the cost to mine them is more than they are worth, many miners will drop out, and the difficulty to mine them will get easier, until the difficulty stabilizes around a place where it is slightly profitable to mine them -- this is why mining has always been a race to the bottom and why eventually economies of mining scale (server farms, etc) would beat the person with 4 GPUs running in their basement.