It doesn't look like the same power law. The #alumni figures for UK universities go 401, 361, 273, 127, 106, 99. The figures for US universities go 2964, 1502, 1174, 889, 828, 658, 581, 568. The US figures drop hugely from #1 to #2 to #3. The UK figures don't.
(If you pretend that Oxford and Cambridge are in fact a single university, then you do get a nice power law fit with a much more negative exponent than for the US figures. But, as it happens, they are two different universities.)
That is interesting (although we would have to do a goodness of fit test).
[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?