Remember that the population of Hungary is about 1/30th of that of the United States. Correct for population size and you may get more interesting statistics.
You would not believe how excellent math education is here, and how important education is in the culture in general. Very stark difference from the United States.
On TopCoder Hungary is ranked #39. On the ACM https://en.wikipedia.org/wiki/ACM_International_Collegiate_P... they are not in the top.
On IMO http://www.imo-official.org/results.aspx the numbers are also not good.