Oxford occupies a similar power law position in the UK
Does it?
The numbers in this newspaper article from 2013 suggest that (1) Cambridge has a substantial advantage over Oxford in total alumnar wealth (as opposed to number of wealthy alumni/ae) and (2) there are other rivals not all that far behind. I wouldn't want to make a large bet that there isn't a power-law distribution there, but it certainly doesn't seem much like the alleged US situation with Harvard alumni/ae twice as rich as any other university's.
[EDITED to add: It appears that these numbers come from the same organization as the Harvard ones.]
Right, in the UK they call it "Oxridge." But if you plot the histogram it will probably look like the power law also.
[Added: Solipsist made good comments that partially account for the phenomenon, and Douglas_Knight pointed out that the figure of $200m+ below should be $30m+]
This article reports that Harvard has 2,964 alumni worth $200+ million, with a total wealth of $622 billion. These figures are staggering:
Note that Bill Gates "only" has ~$75 billion and that Mark Zuckerberg "only" has ~$30 billion, so that they don't account for Harvard's decisive advantage over other universities.
What is going on here? Why would Harvard come out ahead by such a large margin? Its acceptance rate is smaller than those of Stanford, Yale and Princeton, but by no more than 25%. Moreover, this has been true historically
One can ask a similar question of University of Pennsylvania, which is significantly less selective than Yale and Princeton, but has a decisive advantage over them.
Some possible explanations for the discrepancy:
Regardless of which of these explanations hold, there remains a question of why they would hold.
Is Harvard a better choice than other universities for students who aspire to be wealthy than other top schools?