Ever wondered why those blues musicians better than Rolling Stones and rappers (who are brothers) with a more a killa' flow than Eminem who never got their break?
Luck and skin colour. Middle America buys white, doode...
First of all, I have no idea what 'Middle America' is. Second of all, if you were talking about the US, race really isn't an issue. There are many famous Americans of different race. White, Black, Latino, Asian. USA is really just as, or even more multi-cultural than Singapore. There's no issue at all regarding race unless you live in the South (Tennessee, Texas). Think about it, super-minorities in America make it big, for example, Amerie, who is half black half Korean. And many Chinese-American bands hail from Southern California and do absolutely amazingly.
Countries in general I feel only buy white would be Australia, Britain and probably most of Europe. But as you can all see, Dragon Force is one hell of an exception. Herman Li is Chinese, Sam Totman is English, and ZP Theart is from South Africa (I don't know his origin though). So really, it's all down to talent.
However, if you're planning to do anything in Australia, you're pretty much screwed unless you're white. They're pretty racist there. I got rocks thrown at me when I was on a bus.
This is my opinion, being Chinese-American. Take that into account.