Mixed Martial arts competition has been around longer then the UFC
This stuff has been going on in Brazil and in Japan for some time.
I'd guess though, that had it gotten really big 30 years earlier we would have seen a similar progression. Initially the submission fighters would have dominated. BJJ, Catch, Judo, etc. Then the wrestlers would have learned some basic boxing and ground and pound and dominated. We would have then got some kickboxers and boxers that learnt how to use the guard and stall wrestlers on the ground and beat them on there feet. And finally after a couple years, everyone would be a true "Mixed martial arts" fighter, able to function at any stage of the fight.