If you want to improve the output of solar energy systems, why not also run them at night? That's the question researchers in Qatar and Jordan addressed as they successfully devised a system that promises to more than double energy output of current solar power stations.
It is not unprofitable for the corporations who run the plants but only for society as a whole. You have to consider the state funding for research and development, subsidies for construction and operation of power plants, plus the fact that the state runs and pays for the final storage facilities for nuclear waste. All those billions of taxpayer money getting systematically redistributed to the nuclear industry to offset the real expenses of nuklear power, makes it in fact an extremely profitable business. Think about it, otherwise there would never have been a nuclear industry in the first place, at least in western/capitalist economies.