Im not sure I agree with you entirely with regard to companies continuing to mine if the price falls and stays down. There comes a time when a business has to make a decision about losing money. When the cost of gaining a bitcoin far outweighs its value and potentially future value.
For example, I have a 7 gig miner, it makes maybe $0.15 a day, but its costing that in electricity, now I get that for free so its worth running it but if it were costing me say $1 a day in power then I would turn it off.
But you aren't a mining operation. You are using a very inefficient miner running it out of your house. A large scale mining operation running equipment that gets 2Gh/s per watt running in Sweden or something where electricity is 5 cents a kilowatt or less is ALWAYS going to beat you in efficiency. Bitcoin would have to drop to like $50 or so for it to start costing them money. There is no guarantee they would turn off at that point anyway but let's say for the sake of argument they did. So what? You already turned your miner off long before then so what difference does it make? A. Bitcoin isn't going to drop and remain at such a low price and B. If something happened where it did, ordinary miners would feel the pinch long before the datacenters.
For the record I might not be making a living out of mining, however electricity is free because its surplus in my racks I have a bit more than 7 gig of hashing power and what I have is making me money. I used the 7 gig miner (it was the first one I bought and sits in my office for old times sake) as an example. The point I was making is that even if they do get their mining power for 2 gh/s per watt if they aren't making a profit or there is doubt about how much they will make then it will stop, business is business.
I would like to see the figures for a big mining farm out of interest. Sure they must get discount on the equipment but by how much? By my reckoning 2gh/s that cost only $1 per gh/s (wild guess on my part
) running for a year and using 1 watt at $0.05 would make just under $4 in a year. So maybe $2 profit? But then you have the other costs such as cooling, rent, wages, insurance, accounting fees, tax etc. (prices worked out on current BTC value not $50).
I dont doubt they are making a profit somehow but the margins seem very tight to me.
Im not looking for an argument just a discussion.