I mean, it doesn't need to be extreme comparisons. We have gini-coefficient already, which captures similar.

The rankings correspond reasonably to my intuition too, when I think of which have "elite" universities. https://en.wikipedia.org/wiki/List_of_countries_by_income_eq...

The ones I was specifically thinking about were the Puebloans of the American Southwest. There's a famous old paper whose title summarizes the situation pretty well:

"Although they have petty captains, they obey them badly"