[aidenn0]

Don't forget also that the Gracie family had significant Vale Tudo experience, and those rules were very similar to UFC.

Also, BJJ grew out of early Judo, which was less calcified when it was brought to Brazil. Helio Gracie was manhandled by the Judoka Masahiko Kimura, despite home-field advantage[1].

Catch wrestling also had similar rules, but had a culture of secrecy, so was not going to spread in a similar way to Judo.

Yet another reason is simply the fact that weapons were invented many thousands of years ago, so unarmed combat has been unimportant since at least the bronze age.

1: Of note, the Gracies thickened the padding of the mat used because Kimura's throws were known to be capable of concussing people; after throwing Gracie around like a ragdoll for the entire first round, he switched to trying for lock submissions, which he eventually did get (and BJJ names the shoulder lock used the "Kimura" even today).