> I tend to disagree - better to let people sleep.

I'm not advocating to move around the standard work day, but grown adults could just go to sleep an hour earlier. "let people sleep" makes no sense. It wouldn't take away an hour of their sleep.

This isn’t about “grown adults” and their capabilities. It’s about the well-being of society as a whole. There’s a lot more to consider than “when should working people show up for work”?

Note that a significant portion of society doesn’t have a day job — kids, retired/elderly, caregivers & home-parents, disabled and unable to work, etc. In fact, the needs of these groups ought to be prioritized, since as you said, working adults can adapt.

Adults are sleep deprived not because of sun, but because of evening activities - games, reading internet, movies. They value a bit more entertainment or a bit more work more then sleep.

Half a year there is dark long before adults go to sleep and also dark in the morning. Sun is not preventing sleep, but people dont sleep.

You seem to be conflating two problems. The fact that many people stay up too late entertaining themselves doesn’t change how people as a whole respond physiologically to the presence and absence of sunlight, or how that ought to factor in to policy decisions.

The majority of year there is dark long before adults go to sleep. Adults go to sleep at same times as during summer, the dark is not making them going to sleep more.

For all practical purposes, sun is completely irrelevant to adults sleeping.