Think we underestimated the cost of mining. If we look at the current hash rate statistic, the drop is not significant and that means there are still people who leave their machine running. Generally miners won't do that if it's not profitable.
Then, isn't this a paradox, when prices were $3 at the start of 2013, miners were there and now also miners are there, so does that seem to point to the fact that mining is price independent. No matter what the price is there will be miners and sellers.