One could argue that our society USED to be like that. It's only recently that we all started buying houses with closets the size of bedrooms our grandparents grew up in and shared with siblings. It was not uncommon for 3 or 4 generations to live under the same roof and the elderly here used to be revered, not seen as unproductive members.
Societies develop and change over time. You are right, a long time ago Europe was bronze age and cave dwelling and all of that. Society progressed to its zenith, the Grecco/Roman world. Each had rivals, Greece had Persia, Rome had Carthage, and through it all, far to the east was China. Not long after the Native Americans were building pyramids in meso America. The tribes in the USA were building very impressive societies in North America. There was a city around St. Louis (forget the name of it) which was at its peak from 1200-1600 AD. I would have chose to live there instead of London at the same time.
In Europe, Rome fell, and Europe was stagnated for some time, you had the Mongles, the Tartars, the Vikings all ransacking and preventing progress. You had the constant threat of an Ottoman invasion from the east. But through it all, the west thrived in many ways, and ultimately stabilized and reached a new zenith, and we're still climbing.
Arab/middle eastern culture has had its ebbs and flows. East Asian has had highs and lows. Obviously the new world got the short end of that cultural exchange, I would say that although never in last place, they went extinct.
But through it all, one place has been in last place.
Show me the Sub-Saharan version of: Shakespeare, Confucius, Charlemaign, or the like!
I know there are VERY intelligent black people. That isn't the discussion. The smartest person alive may well be black sub saharan. But why are they complete failures at living?