From the point of view of big government types wind and solar need massive injections of tax money because the current state of the technologies involved do not allow scaling them up to a level that absolutely requires centralized command and control. I know several people that employ solar panels to trim their power bills. I know a couple of people that employ small wind generators for the same purpose.
Generally regulatory hurdles and arbitrary zoning restrictions limit the use of such systems. This is no accident. The last thing bureaucrats and politicians want is people operating outside their authority. Technological issues notwithstanding, government is the biggest obstacle to growth of the industry.