I don't think it's a coincidence that very few of the very top of top, best of best, Jiu-Jitsu players didn't exceed in MMA. Guys like Marcelo, Nino, Xande, Arona, Gonzaga,
Bibiano, Magalhaes, Roger Gracie, Palheres.... the list goes on. I'm not saying they were losers but they were never going to be champions.
Sure Penn won the Mundials but he got out of competitive Jiu-Jitsu pretty quick and immersed himself in MMA. And he was a street fighter since grade school and knew how to thorw hands before he ever stepped on the mat. And of course there's still Maia, Werdum and Jacare. But I doubt someone coming from a pure Jiu-Jitsu background and was immersed enough in it to win the Mundials will be an MMA champion. And I don't think Nogeria was top,top tier in Jiu-Jitsu tournaments.