I think the reason plainly is that they are not competitive, perhaps because their advantages aren't important enough disadvantages for horizontal axis turbines

I think the reason plainly is that they are not competitive, perhaps because their advantages aren't important enough disadvantages for horizontal axis turbines. Wikipedia has a short section: https://en.wikipedia.org/wiki/Vertical_axis_wind_turbine#Disadvantages_of_vertical_axis_wind_turbines https://en.wikipedia.org/wiki/Vertical_axis_wind_turbine#Dis... I think people tend to forget that the big wind turbine manufacturers today started out small, experimenting with various designs before they settled on the three-bladed model. At the moment there's a lot of accumulated research and infrastructure present that allows them to erect giant 3-6-8 MW turbines that can take the hammering of the weather for > 20 years. Competing against this is really, really hard, you really have to a big advantage in your favor and perhaps also decades of research and development.