^ Also I think hip-hop is not an as universal genre as pop, rock or traditional rock and roll, beat or R&B music. I mean while I can see my 80-year-old grandma liking a good number of MJ songs, I cannot see her liking anything from Kanye. Yes, hip-hop's popularity grew tremendously and it got to the point that any pop song has to include a guest appearance by a rapper to be popular, but that still remains a genre that is somewhat limited compared to pop or rock music. People from all over the world can like a pop or rock song simply based on the music, even if they do not understand the lyrics, while to really be able to appreciate a rap record you have to understand the lyrics. When I started to like Michael it wasn't for the lyrics, because I did not even understand them, it was strictly for the music. While some rap music can have catchy beats or even a good melody, but generally the reach of rap records and thus rap artists is limited. (The exception is maybe Eminem, who is a huge seller, but I don't think even his reach goes beyond a certain demographics and certain countries. So despite of his sales I still would not call him as universal as pop or rock music can be.)
I'd say the genre itself is very, very popular - you have rappers all over the world not, not only in the US and they do rap in all kind of languages - but any particular rap record or artist has a limited reach. Limited to the people who understand that particular language - and not only that, but who understand those particular social issues and social environment that that record is about. When you look at the popularity of American rap albums, they tend to be way more popular in the US than anywhere else. That's because both the language and the issues mentioned on those records limits its audience. (And maybe that's actually the secret of Eminem's popularity: that he does NOT only rap about the ghetto etc. that black rap albums usually are about. He has a lot of songs about personal issues that even white kids from Europe can relate to. But his reach is still limited demographically compared to pop/rock music.)
