There is a lot of discussion in this
thread about intelligence, Hungarians,
Jews, old central European schools and
coffee shops, etc.

In my experience, the main conclusion I
come to is: Humans are super TOUGH to
characterize, measure meaningfully,
predict, etc. SUPER tough.

E.g., there is the stumbling block of the
usual dichotomy of nature (i.e.,
genetics, DNA) and nurture (i.e., the
environment of their childhood, etc.).

We can try to focus on just the nature
part, but again we get stumbling blocks of
the wide variety of outcomes from,
seemingly, too many factors.

Sure, can give a test with 100 questions
to millions of people and then use the
linear algebra principle components
decomposition to find 100 orthogonal
factors and eigenvalues. Then there is
a claim that IQ is just the largest of the
100 factors. Sooooo, that omits 99 other
factors. Hmm .... Then, tough to have
much faith in IQ.

So, we can suspect that the other 99
factors can help or ruin the effect of the
IQ factor. In my experience, that can
happen.

I'm not Jewish or Hungarian and have never
made any particular effort to have contact
with either, but one way and another by
accident or forces unknown at the time to
me have had some contact. So:

(a) Dad thought that a big advantage would
be a college education so I got one.

(b) Mom thought that a big advantage would
be a Ph.D. so I got one. So did my
brother.

(c) In grades 1-8, the teachers regarded
me as in the bottom half of the class,
maybe near or at the bottom of the class.
So I tended to give up on school or trying
to do well. My parents were fine with
that.

(d) I'm a male, and, as is common for
boys, by the 8th grade my handwriting was
still a mess. So, with that mess, my
accuracy in 8th grade arithmetic was poor,
and the teacher warmly advised me never to
take anymore math.

(e) In the 9th grade, I saw that I could
do well in math so did. My main
motivation was to reverse the 8 years of
the teachers treating me as a poor
student. Sooooo, that was the goofy
reason I got into math. Lesson: A lot of
what happens to people can be from just
goofy reasons that have nothing to do with
IQ or ability.

The school I went to in grades 1-12 was
intended as the city's premier college
prep school. Supposedly 97% of the
students went on to college. Since there
was no Jewish high school in town, the
Jewish kids also went to that school.
Then in the Math SATs, of #1, #2, #3, I
was #2 and #1 and #3 were Jewish. I had
done nearly as well or a little better
than both of them in grade 9-12 math
classes. I had made no effort to
compete: I had come to like math and
enjoyed cutting off insults from the
teachers. I didn't see anything very
special about the abilities of the
Jewish students.

As I continued in math, I heard about
several of the names of the Jewish
Hungarian mathematicians in the OP:
Halmos remains my favorite author. Once I
got von Neumann's Quantum Mechanics and
got through the first half, just some
math, the physics was later, easily enough
before got interrupted by other work. Von
Neumann's game theory work was heavily
around the saddle point result, and that
is an easy result of duality in the linear
algebra of linear programming. I heard
about Wigner since my ugrad honors paper
was on group representations for molecular
spectroscopy. Early in my career, I was
at GE as they took Kemeny's work on Basic
and timesharing, etc. and made a business
out of it. Later I was reading Feynman's
Lectures and saw his remark that a
particle of unknown position has uniform
probability distribution over all of
space. If that space has the usual
assumption of infinite area, then there
can be no such distribution. For the
Manhattan Project picture of von Neumann,
Feynman, and Ulam, once I used Ulam's
result tightness in a paper I published.
Once I published a paper on a fine detail
about the (Karush) Kuhn-Tucker conditions.
Later I saw that the famous paper of Arrow
(mentioned in the OP), Hurwicz, and Uzawa
mentioned a problem, and my work solved
that problem also. The Chair of my Ph.D.
orals committee was Jewish -- the
brightest prof in his department was not
Jewish or Hungarian.

Point: I've never had any ambitions to be
at the top of academics, but I have not
found that work the Jews or Hungarians do
is too difficult to understand or, in some
cases, extend.

As an example of the influence of the
other 99 factors, maybe the brightest
person I knew was my wife. She was
Valedictorian, PBK, Summa Cum Laude,
..., etc. But some of those 99 factors
proved fatal.

Concluding Suggestion: When see some good
work, e.g., the Halmos work on sufficient
statistics, a good performance of the
Bach Chaconne, e.g.,

https://www.youtube.com/watch?v=ngjEVKxQCWs

or the

Rachmaninoff: Piano Concerto no.2

https://www.youtube.com/watch?v=rEGOihjqO9w

etc., just be glad for such good parts of
civilization, credit the person doing the
work, and f'get about whatever 100
factors, nature, nurture, etc. were the
cause.