In ancient civilizations, at least in temperate climates, bare feet were often the norm. Sandals might occasionally be worn, but they would usually be the exception.
Here’s a little bit about Egypt.
My source here is “Life in Ancient Egypt”, by Adolf Erman.
We’re all familiar with Egyptian hieroglyphics, their stone friezes, and their statues. The statues are almost inevitably barefoot.
I like to think of it that bare feet are “formal wear”. Sandals were just these things you might occasionally have to resort to under certain harsh conditions.
Here’s what Erman says on footwear in Egypt:
Egyptian costume, as far as we have already considered it, shows a comparatively rich development; on the other hand the history of the foot gear is very simple. In no point of apparel, in fact, did the nation remain so faithful to old traditions. At a time when people paid great attention to the various gradations of style in clothes and wigs, and when they were also strenuously striving after greater cleanliness, men and women, young and old almost always went barefoot, even when wearing the richest costumes. Under the Old and the Middle Empire women seem never to have worn sandals, while great men probably only used them when they needed them out of doors, and even then they generally gave them to be carried by the sandal-bearer who followed them. Sandals were more frequently used under the New Empire; still they were not quite naturalised, and custom forbade that they should be worn in the presence of a superior.
Finally, one more picture. I like this one because, although Egyptian pictures always seem so stiff, this one manages to capture the flexibility and use of the arch of the foot.