so, who's today's von Neumann?
In the last 50 years, our collective knowledge has grown at a pace that is incomparable to other periods of time. Something that falls out of that is that the open problems in a particular field are much more difficult to solve.
It is also true that the knowledge is much more widespread. For instance, many CS undergrads are expected to learn game theory. What was once an advanced topic is now just part of the curriculum.
Basically the common denominator has risen in a way that is much more difficult for a single mind to seem comparatively impressive.
As far as others are concerned, they're probably members of the Prometheus Society.