Wind, in particular, has a great deal of bureaucracy around it. Environmental issues. Construction codes. Land use issues. Land ownership issues. Air rights. And more. Today, investors have to work through all these in order to put up a wind farm. The reason they still do it is because as an entry into the energy markets it is an incredibly cheap vehicle. (Comparatively speaking.) The technology is just not that complicated. Even compared to fossil fuels, wind is just a dead simple tech. The costs when you don't count regulation reflect that.