So, mining should be extremely profitable? Why would anyone buy BTC for $1400 if he could mine one for $50?
That's for the next generation, 28nm products.
If you buy a 250Ghash/sec ASIC miner which consumes about 1000W and costs 11,875 dollars (65nm product) it's different.
Than you can mine 0.138BTC/day.
That costs 1000*60*60*24/3600000=24kWh
That's 174kWh per Bitcoin.
Electricity costs 20cents/kWh => 34.8dollar
Harder is to determine how much BTC you can mine, before your ASIC is written off. Not to mention the increase in difficulty.
But it's a whole lot more than 50dollar/BTC.
And of course, the renting product I mentioned can only be pre-ordered, and not everybody can invest in such an ASIC.