They never existed. Fighting is still primarily about physical tools, which is why guys like Jon Jones and Chris Weidman can pick up MMA and be elite fighters almost instantly. There was no such thing as a "new breed" of fighters who actually trained MMA as kids (instead of traditional martial arts and/or wrestling). Well, there might be some of those kids, but the point is that it doesn't matter. A person with better physical fighting abilities still stomps them.
That's why all this crap about "evolution of the sport" was junk as soon as people figured out basic subs and wrestling. It's been the same sport since like 2002, if not before. Which is why there are people who are still good now who have been fighting since like 2002. Looking the half of the top four weight divisions, actually: Werdum's first fight was in 2002 and Robbie's was in 2001. If you keep going down, Aldo's first fight was in 2004. So was RDA's.
So it's like that song by The Who. Meet the new breed / same as the old breed.