Most people say that it's very difficult to be a white rapper because the world does not want to hear a right rapper but then again statistic shows that this is not true at all whatsoever no matter how hard people want to believe that. For example Eminem had a hard time getting into the music industry because he was a white rapper path that he prove yourself with his sick lyricism people started to change their minds about the whole ordeal. They say that Eminem was the one who pays the road for other white rappers to be in the music industry because if not for him a lot of white rappers would probably not be accepted as a individual as opposed to a rapper.
One thing about why rappers that you don't see too much is the use of the N-word because the N-word is used exclusively by black rappers of the fact that white rappers don't tend to use his word kind of adds a new twist to the meaning of rap since almost all wrapped music that has ever been made has at least one N-word included within the song. I have no idea what rap will look like in 10 years but I can tell you that rep has evolved so much from the date was born until today though the fact that it change ended a 360 does no way in knowing how well rap will be going in a few years from now.