'Joe Redheart' (lol) would be playing probably if conditions in the Native American community and on reservations weren't so completely ground down. There used to be some major Native American athletes in the old days (and I do mean 'old'). The Eastern bloc athletes are in basketball (I think there are more ex-Yugoslavian and Turkish ballplayers than white Americans), boxing (Vladimir & Vitaly, anyone?) as well as gymnastics, hockey, soccer, etc. Soccer allows for some good comparisons, b/c it's one of the truly global sports, so you have a broad sampling to measure interracial performance.
On your running example, it's dominated (at least distance running is), not by formerly enslaved African-Americans, but by never enslaved, high-altitude training Kenyans, Algerians and Ethiopians, who are small, slight and fleet of foot. But they are still African, though. Lol
As for those East Asian societies, I think it's just a matter of time. And, in all fairness, let's not forget that there is a certain amount of cultural capital that we ("we", as if you and I are doing any high-dollar hooping, lol) bring to the game, particularly sports that black athletes have placed a major imprint. I'm not denying the dominance, just doubting race-driven genetic dominance, thinking instead that it's environmentally-determined dominance.