I live in Northern Europe and in this time of years it is not uncommon to have cloudy days with little light (you need lights on indoors) for weeks at a time. I wonder people from before artificial lighting had adaptions to lower light levels.
If the suggestion is that I reduce my working hours drastically during the winter I'm all for it, but it is getting a little tiresome that supposed scientists completely ignore the fact that a pretty sizeable chunk of the worlds population lives pretty far north and have done so for thousands of years.
The research may very well be right, but it's not particularly useful if you don't address the fact billions of people live in areas where you're recommendation don't make sense.
This is a way of amplifying that plenty of people live north of other people. Whole countries.
Today, where I live (53 degrees latitude, northern hemisphere), the brightest point of the day is just about 100W/m². That converts to about 12000 lumens, but that is only at the very brightest midday hour. Before that or after that, it is only about a third of that. There are plenty of days where it doesn't even reach 100W/m².
On those days, daylight is more dim than regular lamps even at the brightest point of during the middle of the day.