There’s been research on this point and it supports your thesis. After adjusting for applicant scholastic aptitude, the additional benefit from attending an elite school is “generally indistinguishable from zero.”

Excerpt from article*: In November 2002, the Quarterly Journal of Economics published a landmark paper** by the economists Stacy Dale and Alan Krueger that reached a startling conclusion. For most students, the salary boost from going to a super-selective school is “generally indistinguishable from zero” after adjusting for student characteristics, such as test scores. In other words, if Mike and Drew have the same SAT scores and apply to the same colleges, but Mike gets into Harvard and Drew doesn’t, they can still expect to earn the same income throughout their careers. Despite Harvard’s international fame and energetic alumni outreach, somebody like Mike would not experience an observable “Harvard effect.” Dale and Krueger even found that the average SAT scores of all the schools a student applies to is a more powerful predictor of success than the school that student actually attends.

* - https://www.theatlantic.com/ideas/archive/2018/12/does-it-ma...

** - https://www.nber.org/papers/w7322

I wonder if a similar analysis could find whether there is a 'skull and bones effect'.

Their magic recipe is putting a bunch of smart, mostly rich, people in one place and then telling them they are part of an exclusive community. Then they give them access to the older successful members of the community and constantly remind them that once they are the older successful members they need to help out the recent grads.

Sounds a lot like Freemasonry, but unlike Feemasonry, it seems to be actually working as intended.

You could also use the formula, "rich, mostly smart".