The Gracie's have been guarding this secret very closely for decades. They have been lining up certain fighters they know they can handle while simultaneously avoiding other fighters at all costs. Gracie Jiu-jitsu is a carefully controlled myth.
Yet they changed the face of Martial Arts and no one can be a champ without knowledge of Jiu-Jitsu.
Too bad you weren't around during the days when our doors were open to all challengers who would get 10 grand if they could defeat a Gracie.They accepted all comers and turned down no one. They were the only ones that really put their money where their mouth is. It would be great to see what you could do.
BTW, you still can. Just walk into any BJJ school and challenge the instructor. It's done all the time and not considered out of line. I remember back in the day a professional fighter from Japan flew all the way to Cali to drop in unexpectedly to challenge Rickson. He left a bloody mess.