[1] http://www.theatlantic.com/entertainment/archive/2013/08/the...
Countries as large as the US, India, China, etc., have large enough populations that someone in them should match the "genetic ideal" to excel at a certain sport. It is economics that prevents them from doing so. Either their country or culture doesn't value the sport and thus doesn't spend money on it, or they must spend too much time earning to feed themselves that they can't train.
Or that particular person has just never tried the sport. Or there are people who are actually more genetically suited to the particular sport but are discouraged from trying because they hear the current theories on what makes a genetically suitable athlete for that sport.
All we know is that Kenya as a country has the ability to produce excellent marathon runners. To heap all of that on "genetics" is grossly short-sited.
Within a breeding population, height tends to follow a normal distribution. Depending on the standard deviation, there will be a few Japanese taller than the average Dutch. But there will be far more Dutch than Japanese among the very tallest men. This is a simple example, but in a sport where height matters, like basketball, there will be far more Dutch who are good at it than Japanese, and far more Japanese than pygmies.
Certainly culture matters, especially in sports where intelligence matters more and raw physical talents matter less. But genetics also matter.
Yes, it could be said that the Japanese do not value basketball because they have historically not found success in it on the international scale, which would be because of their genetic predisposition to being shorter than even the Chinese. Genetics shape culture and culture can reinforce genetics. But it's not all about genetics. That's my entire point: there is no single variable that can claim why Kenyans run so well. But people want to say that it's genetics that make a good marathoner. That's just not the case, it takes both genetics and environment.
This is not a novel concept, but for some reason when it comes to lay people talking on the internet about sports, they don't want to admit it. The world is complex, there are shades of grey, nothing is black and white.
- http://suite101.com/article/why-are-the-dutch-so-tall-a55753
People in my hometown love baseball. The next town over they love football. My hometown has never produced a professional or semi-pro football player, and the next town over has never produced a professional or semi-pro baseball player. But they each have had one or two people at least show up on the rosters of a professional team in their favorite sports. That's a difference of 11 miles, with highly mobile people who do intermarry between towns.
There can be significant enough differences in the culture of particular communities to allow for varying sports values. I would expect smaller towns to tend to emphasize one sport over all others, to the point that the townspeople in large part will live and breath that sport in a way that people in larger communities with more diverse sports options would not.