Jay Z , I'm not saying he was the best rapper of all time (but he is pretty good).
Wayne and Kanye have successful careers, but they're newer.
Eminem had a 5-year recluse period after Encore.
Rakim lost what made him so great in the 80's and he barely makes music.
Biggie and Tupac died.
Nas stagnated. He rapped the same way then as he does now with no changes. It got a little stale.
Jay Z has the money, the record label, clothing and he's been with hiphop in all of its eras every since he came out. One of the most recognized names, but most of all, he adapted to whatever era he was in.
He never really fell off. He was always one of the greats ever since he came out. And even now he has high status.
I think of all rappers, Jay Z handled his fame the best for this reason.