It's ALL about the electric rate, the efficiency of your mining gear, how much power you have to use to keep the gear COOL and how much you had to pay for your mining setup, and sometimes incidentals like "pay for help if you have a Mega Farm"....
I would agree on electricity rate. One a lot of people look over is VAT/Import taxes. Some places a 20-25 percent tax could kill ROI.
Mining is still alive and will just takes a lot of variables to line up for it to work.
As they have said, elec is everything. Personally I got 0.07$/kwh, but a 25% VAT/import tax. AND the UPS bastards are probably gonna send me a bill for "handling" as well (For the S7). If I remeber correctly, they wanted 600$ in "handling fees" for 5x S1's back in the day.. I'm worried
Edit: I also need to pay a 28% tax on all BTC profits.. I actually don't know yet how I calculate this when I'm mining, and not trading!
Yeah in my case at 13c kwh that boat don't float...so unless I just want a toy (like the sidehack 8gb usb stick for 25 bucks with the ROI of a smile ) I got zip for any ideas
on wtf I'll ever be able to mine with again and be within 1000 miles of sighting ROI land