Morgan Stanley say bitcoin mining only profitable above 8600 dollars. I'm not sure this is correct though, especially if future valuations come anywhere close to fruition.
This is not exactly. It depend on the price of electricity and some policy of government in country where you're living.
According to Elite Fixtures, the cost to mine a Bitcoin in Venezuela is cheapest $531 and Republic of Korea is the most expensive $26,170. United States is $4,718. Many Asia countries and some East European countries have the cost to mine a Bitcoin is cheap as: India, China, Uzbekistan... they just need $1,100 - $3,500 to mine a Bitcoin.