While having a much smaller population (10M), Hungary places 4th in worldwide medal rankings on the International Mathematics Olympiad [1] behind China (1.5B), USA (300M) and Russia (150M)
If we're talking about von Neumann, or even just the math olympiad, then clearly we're not talking about how well the education system serves the 50th percentile. It's possible for a system to be awful for most, and somehow find and train the top few percent brilliantly.