That's the wrong metric. Scrolling is less straining than moving eyes (or even the head in this case).
People complain a lot about "wasted screen estate" but the first version that "doesn't waste blank space" is completely unreadable to me on desktop, I want to stop reading after the first line.
That website really grinds my gears. He's the equivalent of an HN influencer I guess, because I seem to come across him every three days. Like the Stratecherry guy. And it's so naff. It's clearly designed to look like that on purpose and it's kind of a thumbing-your-nose at your audience thing. "My words are so important that you can get fucked if you want max-width". It REALLY annoys me way more than it should. After all, it's just another dude on the internet.