It only costs more power because of how many miners there are. The difficulty increases the more people there are to mine in order to keep the block finding tim

It only costs more power because of how many miners there are. The difficulty increases the more people there are to mine in order to keep the block finding time somewhat consistent. If we had 50% of the miners go away today, it would still take about the same amount of time to find a block because the overall difficulty would be lower too. Just one company in China, bitmain, has over 28% of the entire network. They are also the company that makes the best ASICs and they appear to be liquidating their equipment in China and starting to move to the US and Switzerland.