Similarly, of the nine active white players who are in the NBA top 50 in career win shares, eight grew up abroad.
This is a pattern that needs some explanation.
But, long term, I can see two plausible explanations for this pattern: the first would be that star basketball players are merely genetic freaks with culture having no effect So, because there are more whites outside the U.S., there are more white genetic freaks from outside the U.S.
The second is that we are witnessing a classic example of disparate impact discrimination against whites within U.S. basketball.
Ex-Yugoslavia and Lithuania have been outstanding at basketball as far back as I can recall. They have been highly over-represented, which suggests that nurture plays a role (although, those two places are pretty tall on average, which might be why they took to basketball so avidly).
In contrast, much of the Europe isn't well represented in the NBA: the British Isles (the only NBA player I can think of was John Amaechi, but he was awful, although that was because he was gay and hated sports), France (Tony Parker being the exception that validate the tendency -- his father was a black American playing ball professionally in Europe), the Low Countries (7'4" Rik Smits being the best illustration of sheer height triumphing over a culture's lack of basketball orientation), Poland, Russia, Ukraine, Scandinavia, etc.