While it's heavily maligned, this was one of the points of The Bell Curve. 200 years ago, the smartest and dumbest person both probably lived and died on the s

While it's heavily maligned, this was one of the points of The Bell Curve. 200 years ago, the smartest and dumbest person both probably lived and died on the same farm. 100 years ago, it wasn't noticeably different. Around the 1920s/30s, society started segmenting the higher end out into higher education and then completely different career/life paths. Fast forward another 50 years and people on the higher and lower ends of intellect rarely meet. Think of the people you interact with on a daily basis - unless you're doing things completely outside the realm of intellect - and you'll start to realize that the vast majority of them aren't far off from you intellectually. This applies at the top and bottom.