It's because people learn music from their parents. I knew about Sam Cooke because my pops listened to him, and other artist from multiple eras, and that's how the classics are passed down.
There's people out like this, J dilla got stans that are young kids because they learned about his music from brother, or somebody else older in the family
I never seen Wilt Chamberlain play a game or do any goddamn thing, but I can't remember a time ever I didn't know he was, I don't think anybody did, because he was that big of a figure where it was just in grained in the culture, that's how black artist use to be, Michael Jackson didn't come out talking about, man fukk what James Brown doing, that's that old shyt, he payed homage to james brown and carried on the tradition.
Somewhere along the lines the tradition got broken