It would be more realistic if people were able to sleep in places other than a tent or hut - on the ground under a tree maybe.

Currently, in scenarios with a solo start, if you don't get a tent double-quick your villager becomes sleep deprived and incapable of any action. But in the real world they would lie down wherever.

The sleep might not be as restorative as if they were in a shelter, but at least they could carry on for a bit longer.