They have - they have risen with teh CPI, over time, just not as fast. "In comparison" is, as I pointed out, not the critical matter. If electrical prices rise as the CPI rises, the payback on the initial investment is faster - whether they match the CPI or not. I didn't miss that, I pointed out its assumptions were not realistic - and also, that even so we were talking about the most expensive possible real life setup of solar power, and comparing it with heavily subsidized and scale-economized delivery of other source power. And even in that comparison, it almost makes straight economic sense. There is quite a bit of benefit in sellling power you are not using - and as you point out, a residential home demand is unlikely to match the overall demand curve, and in particular a private home is likely to have power to sell at peak solar times. And if peak demand is offset from peak production, the averaging of price for residential still favors the payback - the homeowner is selling at peak production, which would not match peak demand times or highest prices, so they are getting a break there. One reason it's not standard. Huge subsidies are reserved for power companies, coal mining companies, nuclear reactors in need of waste storage, etc.