I know loads of white people, white people who don't listen to hip hop, who know of him. And they know him as "the rapper on tv," "the safe rapper for their kids to listen to," "the rapper whose work they are casually familiar with (Mama Said Knock You Out, songs with Boyz II Men, a couple other hits of his)." I think the reason he's not included with your list is because he was THAT rapper before Jay-Z, Eminem, etc. Most of the white folks I know were familiar with him from the movies, tv, "being famous," before Eminem came out and before Jay-Z appealed to white folks.
"Your current frequencies of understanding outweigh that which has been given for you to understand." Saul Williams