When the difficulty gets to 2Million mark price for BTC will have to be $120 coin to maintain mining profitibility..
Wouldn't that be dandy?
Only, $120 at Difficulty 2,000,000 is completely meaningless as a data point of itself. Mining may be profitable at that point, but a mining operation is something that happens over an extended period of time through many levels of Difficulty and price points.
I think that many miners are making a fundamental mistake by valuing the profitability of their operations in terms of Dollars. If you believe that the value of Bitcoin will increase over time and that the value of the Dollar will decrease over time it is completely irrational for the cost basis of your accounting to be in Dollars. Sure, a mining operation may be able to net you some Dollars, but unless you are able to demonstrate that it will net you more Bitcoins than some other method (like buying Bitcoin on an exchange) the cost of that lost opportunity means that you lose Bitcoins. Take a look at what it cost to build your rig, in Bitcoin, at the time you purchased the parts vs. how many Bitcoin it has actually delivered for you. Then figure out if you actually ended up with more Bitcoin than you could have purchased on an exchange at that time...
You may be surprised!
If I had invested the $1100 I did directly into bitcoins instead of mining equipment, I would have had over $20k in bitcoins now. Unfortunately, I did not. But I did not for good reason - that $1100 was an investment I could not afford to lose. By "investing" it into mining equipment, I hedged the risk to a reasonable degree (since I could resell the equipment I bought for 90% of what I paid for it, easily), and thus was able to make the investment. If I had only been able to invest in coins themselves, it would have been something along the lines of $100 or so.
