Just as important as the electricity rates is the access to technology.
With the big boys investing millions into chips at .3 to .1 efficiency to mine for themselves they have no incentive to sell to retail or other competitors.
actually they may believe what you just wrote. but they will crash the price of btc if they don't keep small guys in the game.
why invest in holding btc if only 3 to 4 places control the supply?
unlike diamonds which have real use other then bling, drill bits come to mind
btc is purely a cash substitute. I can't see an investor wanting to hold 100,000 coins in the way an investor holds shares of APPLE (any company) if the mining is centralized to 3-5 companies.
I also still see miners in the home as space heaters. I am not sure why
DeLonghi has not merged or started a joint venture with btc in mind
http://www.amazon.com/DeLonghi-EW7707CM-Safeheat-ComforTemp-Oil-Filled/dp/B000TGDGLU/ref=sr_1_1?I totally agree. If you just buy BTC and then Bitfury would want to crush KnC or vice versa by dropping the price, thereby crushing the value of my BTC 'investment', then it would be stupid to have such investment in the first place.
For mass consumption, space heaters is one possibility, second is, perhaps, routers. Everyone uses a router. Why not add low power hashing chip(s) to it?
Third-refrigerator. It releases a bit of heat already, so why not a bit more while hashing.