Mixed Martial Arts began with a sort of school-yard-argument ethos. If you put two guys in a fight, who would win? Wrestling vs. Karate, Brazilian Jiu Jitsu vs. Boxing, Taekwondo vs. Judo? MMA was a proving ground for the efficacy of combat disciplines; a place to put into practice martial arts often more given to sparring and theory than full-contact fighting.
When the dust cleared at UFC 1, questions were answered. BJJ was king.
Since then the sport has gone through iterations and evolution. Wrestlers took over (and still form the fundamental bedrock of modern MMA), strikers are now thriving; high risk kicks and attacks once thought the fantasy of baggy pants wearing senseis have made their mark.