Russia and China have a huge tradition in preparing and participating in those competitions, while in US, I found it's more like of a hobby, so I'm not surprised given both founders are Russians.
While P(Russian|ICPC Winner) is high, P(ICPC Winner|Russian) is still pretty low :) Also, Illia is Ukrainian, not Russian, but it's nitpicking.
ICPC is a great way to start your career if you were unfortunate enough to get born in a noname city somewhere in ex-Soviet Union, thus people are pretty motivated to do well. In US by the time you graduate you already have few internships in your resume, and are pretty figured career wise, so naturally the benefits of ICPC are less attractive.
Don't get me wrong, I have great respect for people with high prizes in ICPC, which is way more difficult than IOI in high school. I was just stating the fact.
ICPC is a great way to start your career if you were unfortunate enough to get born in a noname city somewhere in ex-Soviet Union, thus people are pretty motivated to do well. In US by the time you graduate you already have few internships in your resume, and are pretty figured career wise, so naturally the benefits of ICPC are less attractive.