We are talking about technology as such not necessarily economically competitive.
I wouldn't consider the technology of solar engineering mentioned in your link economically competitive either.
Doable but not cheap.
The same is true for the technology to prevent climate change. It exists but it was expensive.
Interestingly, it's still expensive now because even though the basic technology is cheaper, the timeframe is much shorter, so we have to achieve more in less time than if we had started earlier.
The availability of economically competitive alternatives to fossil fuels (like cheap solar + batteries) is a very recent development.