> Why did it take until the late 20th century for Brazilian Jiu-Jitsu to develop and the Gracie family crush almost all other unarmed martial arts at the start

> Why did it take until the late 20th century for Brazilian Jiu-Jitsu to develop and the Gracie family crush almost all other unarmed martial arts at the start of MMA, when humans have engaged in unarmed combat for millions of years and every major country has long lineages of specialized competitive martial arts and tremendous incentive to find martial arts which worked and quick feedback loops? This one is easy. Because Gracie jujutsu (spell it right please) with its emphasis on ground technique is only effective when you are unarmored and your opponent is unwilling to use lethal force. In military and/or life and death situations it is a good way to get yourself killed by a trained opponent. It’s not surprising at all that Gracie/Brazilian jujutsu only developed after the popularization of MMA like sporting competitions with rules that the Gracie brothers learned to exploit.