Makani had huge amounts of capital from Google to work with. As you point out there are other much smaller players in the field who keep the generator on the ground and generate power from the upward pull of the tether. I worked at one of these startups. But after Google canceled Makani it became very difficult to find funding because angel investors figured that if Google got out of the game it must not be viable. And so we folded.
> - On the edge, possibly near to commercialization: https://www.ampyxpower.com
A CGI video does not convince me that they're near to commercialization.