The original Pioneer Fund funded Minnesota studies very rarely studied twins separated at or near birth and raised in very different environments. For most of the twins, the separation happened much later, or happened early but was temporary and the family was reunited, or the parents died and two sisters each raised a twin, and the like. The notion is false that the Minnesota studies all this flowed from showed people mainly raised from birth in very different environments. It did not.
It's a religious belief - we are the Brahmin, we are the chosen people, dressed up in 21st century Calvinist/liberal clothes. We are born successful or not successful, due to nature, not nurture or environment. It's scientific Calvinism. Of course some people flock to defend it in a way they wouldn't for some aspect of quantum theory - as I said, it's a religion in pseudo-scientific form. It feeds people's egos, especially people born to some form of privilege who have not accomplished all that much, and some people race to swallow from that hose as fast as they can.
The history of the funding of all of this is the old Pioneer Fund which started out showing Nazi eugenic films. They funded the original Minnesota twin studies all this field flowed from.
I should note this appeared in The New Yorker three years into Tina Brown's editorship, this kind of low middlebrow garbage didn't show up in The New Yorker much before that, but it became commonplace after she came in.