Re: Why is the United States so much better at basketball than the rest of the world?
The simple answer is wealth I think. In a lot of poor countries you might not ever see a basketball net. You kind of can't play basketball without a net, so that could be a potential answer. I would think this is why you don't see too many South American players except from Brazil.
Another factor would be population. If for example 1/100 people has the body/athletecism/interest/skills to be an NBA player, and we say that 1/100 of those players actually make it through to the NBA then it would stand to reason that the US's 300 + million people would produce more NBA players than Canada's 30 million people.
The last big factor that I can think of is that in certain countrys there are more popular sports. In Canada there is hockey, in Europe there is soccer/rugby, and in some African countries they throw sticks at dead bodies.