It's important to consider that rap/hip-hop lyrics are deeply tied to social issues. For a middle-class white kid, it's not super important, but for the audience that was also making the music, this is why it took off. The music was new with a message, and even if you didn't understand the message, you could feel the power behind the music. Then you had producers like Rick Rubin, and labels like Def Jam, that knew they could market the music to white kids in the suburbs. I was one of those white kids in the suburbs, and my friends and I would listen to more "underground" hip-hop/rap radio stations in the very late 80s/early 90s to find music that had a message behind it and was honest (even if we weren't the target).