First thanks for your input. Now here is my take :
There are more Americans than any other nationality in the UFC, and majority of them are former college wrestlers.
Then for the other countries a big lot of them have no culture of wrestling in their country, like Brazil, Canada, the UK, western europe, Australia, New Zealand, Mexico, Japan... The only ones with a real freestyle wrestling background are mainly russian and ex-ussr countries.
So i beg to differ, there are more folkstyle wrestlers than freestyle in the UFC. Then if you talk about the amount of wrestlers in the world, yes freestyle and greco are more numerous of course because folkstyle is limited to america. But not in the UFC.
The fact that you can't lock hands in folkstyle you have fewer takedown techniques. Freestyle is superior when it comes to takedowns and throws. Folkstyle is Superior when it comes to ground work because the folkstyle ride is useful in MMA, whereas the freestyle groundwork is useless. But once both athlete learn bjj, get to a purple-ish level, and develop a good bjj top game, the advantage that folkstyle did bring becomes less relevant while the takedown superiority from freestyle still is. A pure freestyle wrestler with good bjj will be more well rounded/dangerous than a pure folkstyle wrestler with good bjj.
Yes DC and khabib use a mix of different grappling style, it is true. I said it for DC anyway. They're style mainly freestyle wresters because DC spent years training freestyle at a way higher level than folkstyle for the Olympics, and Khabin said himself than freestyle is what he prefers. But yes they're mixed grapplers if i can say so.
GSP trained wrestling since he was 16y old and he trained it extensively with the Canadian Olympic Wrestling Team which had athletes like Zimmerman at the time. I don't know where you get the idea that he never wrestled. Never competed you meant ? Yes, but he still wrestled. A hell lot.