There are three relevant regions in cost/benefit space here; call them A, B, and C.
Region A, producing energy by way of wind/solar costs sufficiently less than the price of that energy to make the capital expenditures a good use of money for individual market participants.
Region C, producing energy by way of wind/solar costs more energy to make than we get out of it. This is allegedly the case for ethanol.
Region B, the dollar cost of building and maintaining wind and solar might too high, while the energy cost might not be.
In region A, subsidies are unnecessary - people will build anyway.
In region C, subsidies actually raise energy prices.
In region B, subsidies could make energy cheaper.
If you believe the government doesn't do anything unnecessary, then the existence of subsidies shows we're not in region A. If you believe the government doesn't do anything harmful, then the existence of subsidies shows we're not in region C. Honestly, I'm not sure the existence of subsidies shows us much of anything. There is a world where they might be helpful, though.
Region A, producing energy by way of wind/solar costs sufficiently less than the price of that energy to make the capital expenditures a good use of money for individual market participants.
Region C, producing energy by way of wind/solar costs more energy to make than we get out of it. This is allegedly the case for ethanol.
Region B, the dollar cost of building and maintaining wind and solar might too high, while the energy cost might not be.
In region A, subsidies are unnecessary - people will build anyway. In region C, subsidies actually raise energy prices. In region B, subsidies could make energy cheaper.
If you believe the government doesn't do anything unnecessary, then the existence of subsidies shows we're not in region A. If you believe the government doesn't do anything harmful, then the existence of subsidies shows we're not in region C. Honestly, I'm not sure the existence of subsidies shows us much of anything. There is a world where they might be helpful, though.