I can absolutely agree on the turbo yeast part. I have fermented some apples with turbo yeast and they were able to bring it up to about 21% (but with added sugar).

I just tested a turbo yeast sugar wash I have and it's sitting at exactly 21%

Dare I ask why you happen to have turbo yeast sugar wash lying around?

For making neutral spirits as the basis for gin

In my uni days a flatmate made "wine" like this, surprisingly drinkable with a mixer.

How "recent" are the developments of those turbo yeasts though? I wouldn't be surprised we figured out how to create those only in the last century using modern scientific insights.

It was popular to study fermentation, because nobody knew how it worked. Anton van Leeuwenhoek (the "inventor" of the microscope [0] around 1670) was the first person who saw yeast cells, but nobody knew what it was. In 1880s people realized what yeast is and that it was behind fermentation. Around 1900 breweries began using (their) specific yeast string. Yeast was the first eukaryote which genome was completly sequenced, in 1996. So, yes, research in yeast is relativly modern.

If you are interested in this topic, I can recommend the book "Proof: The Science of Booze" [1] which has a chapter on yeast and a following one on fermenation.

[0] https://en.wikipedia.org/wiki/Antonie_van_Leeuwenhoek

[1] https://www.goodreads.com/book/show/18222694-proof

I am curious actually, thanks for the info!

What does that matter when they're replying to "Once you go over 16% or so alcohol, no cell will grow in it. That’s why alcohol above that is distilled"?

Because it is quite common for common knowledge to be outdated for decades. Even among professionals, let alone the general public.