Yes, you're probably right about us only hearing their export quality. Those markets are huge, so to be able to have your music exported is really a big achievement for them. I think it's easier for the really good SA bands to get their stuff played overseas. But to actually penetrate the big overseas markets (US & UK) is quite a different story...
We only get exposed to export quality foreign music. Scrounge around facebook, myspace and garageband, and you'll realize SA is way up there with the really amazing muso's of the world.