Compared to traditional wind turbines, this solution trades an enormous amount of complexity, maintenance, etc for small reductions in material cost. We should be churning out traditional wind turbines for cheap instead.
The algorithms to control the kite are pretty straightforward, the complexity to self launch would be a bit tough but it's easy enough for a human to do so there is no need to include that complexity for the use cases this is targeting. This wouldn't be a set and forget solution, not yet.
The kites will wear out relatively quickly but they're cheap to replace.
I consider myself a pretty skeptical / practical Engineer and I don't see any show stoppers, I think it'll fit the niche they're targeting quite nicely.
So? These (kitepower and skysails, but there are more) are long standing 'competitors' of Makani, all existing for far longer than 2020 when Makani went down. Just because Google gave up, not everyone else also gave up. I mean, Google also stopped Google code, groups and google+, yet similar products are still triving.