And then there is China - remember that IOI for instance accepts 4 people from each country.

After all it all comes down to individuals. In Poland, there is famous informatics high school teacher who is credited for producing most IOI/IOM medalist per high school pupil in the world I believe.

They have special training program there. Another thing is to actually find geniuses, obviously. And if you don’t believe in geniuses, meet Jake - https://m.youtube.com/watch?v=OR36jrx_L44

For example, Jakub Pachocki (director of engineering of OpenAI) who graduated this high school, actually was on the verge of getting F from maths in his previous high school, because of problems being to easy I believe. Then they made the transfer where he could finally thrive. Interestingly, he wanted to do phd in 2 years in University of Warsaw, but people there didn’t want to allow it just because so they lost him - he went to do his PhD at Carnegie Mellon.

To summarise, from what I understand formula would be something like genius + great, inspiring and allowing teacher(s) + special personalised teaching programs + supportive environment.

Also don’t assume that these outliers are testament to the level of education of general population.