Will mining continue to stay good for the next five years? How can we insure that it will? I didn't want to ask this in the Mining section because it seems all the talk there is about particulars of the technology.
I look into my crystal ball and the reply is "answer hazy, too many variables to KNOW".
Just because ROI doesn't manage 1-2 months (or even 6-8 months in most cases) any more doesn't mean mining is dead though.
It just means it's a high-risk VERY high yield investment instead of a high-risk CRAZY HIGH YIELD investment.
12c/KWH though is a VERY HIGH electric rate to try to mine at - most options for mining WILL lose money with that kind of rate, and the others that CAN make money won't make nearly as much when you're feeding the power company 50% or more of your gross mining income. It's less of a factor if you have to heat, as it will offset some or all of your heating bill, but most places that's only PART of the year and some places it's a very SMALL part of the year.
IMO if your power costs much more than 5c/KWH don't plan on achieving ROI on any current coin. If you plan to get the system anyway, mining to help pay off PART of the cost of the system makes sense even at that 12c/KWH the other poster talked about, but NOT for serious long-term intend to make money miners.
Block halfing does NOT "decrease the supply by half" - it just reduces the rate the supply is ADDED TO - which is minor any more for Bitcoin as over 75% of all Bitcoin have already been mined.