People didn't used to expose themselves to as much direct sun and covered themselves with a lot more clothes. Traditional clothing in arid sunny areas typically covers everything, look at people in the middle east today.

I live in a very sunny desert area and it's kind of funny when people assume people from here would be "more tanned". We stay in the shade, the sun will kill you! Anyone working outside is wearing wide brimmed hats and typically has all of their skin covered with clothing even in the heat, people typically have their faces covered with cloth as well.

Spending time outside with minimal clothing in direct midday sun is a modern weird behavior.