This. It almost only applies to desk jobs. Production workers can’t just work a day less and keep the same output, and if they can’t do it, people like me who are responsible for keeping the production running as part of their job(electrician in my case) also can’t work a day less.

If companies wanted to do this, they’d have to hire more workers to give everyone a 4 day week. But all this would do is create more costs for the company

That’s technically true and also the reason why a 60FPS locked game can indeed look smoother on a 120Hz display compared to 60Hz. Because 60FPS don’t always hold a steady 16.67ms between each frame so it could happen that on a 60Hz display you’ll see a frame twice and skip another one instead.

Nowadays you ideally have a monitor which supports variable refresh rate so this becomes a non issue because every single frame now gets his own refresh.