Like Larry Bird said, the league could use a few more white superstars to bring in more white fans. It was true in Bird's time, and it's true now. In his autobiography Giant Steps, Kareem said it's easier for a white kid to relate to Bird than Magic. You need white players on Bird's level(or close to it) to market a predominately black league to suburban whites. Every group roots for its own. It may not be PC to say it(and its a sad commentary on the human race) but it's true.
I'm not sure that's entirely true, because the majority of fans at the games are white people. Black people support the league, but white people support the league while spending money. Don't get me wrong a really good white American born player would do great for the league, but the NBA hasn't seen one of them since Bird.
In sports I don't think white people have a problem with rooting for black people as much as they get tired of the culture that most of these young black stars associate themselves with. This brings up some interesting social topic of decisions for blacks that involve double consciousness.