I mean - consider for a second that we currently have the most comprehensive martial arts practice in all of history, with the largest humans, best sports science, and all that.
Any top UFC fighter from the past decade could probably beat the fuck out of anyone ever before the year 1980. Isn't that wild? Dudes who have (probably) watched Rick and Morty could beat the piss out of Alexander The Great or whoever the fuck. And it wouldn't even be close.
Biting and eye gouging is banned of course, but even if it wasn't, Brock Lesnar isn't letting you even get close to that. I mean, speaking of Brock, even big pro wrestlers - medieval blokes would shit their pants on sight if they saw Scott Steiner going freakmode off the roids. Perc Angle. Big Show - like what - he's a literal giant.
But what about Mark Zuckerberg? He's a big guy. He does his MMA. I think give him a month to train and send him back in time. Hate to hand it to him, but he would crush.
Material analysis brained. Follow the money. If Muay Thai bred a shit load of elite all rounders they'd go to the UFC. That's what's happened with every other martial art that's fed into UFC. That's why there's so many foreign fighters populating the leagues - a 30k USD contract to get concussed isn't worth much in America, but it buys you a home in many places in the world.
Blokes in the army are trained to kill... It doesn't matter. How are they even reliably punching Khabib in the temple, when he has shown himself to clearly be very hard to even take down or knock out, let alone one-punch. Go for the punch, Khabib double legs takedowns and then starts mauling you with his utterly impeccable wrestling skills. Have you ever sparred? It's fucking impossible when someone has a large skill gap over you.