Show me one MMA Fighter, who knows how to throw proper body shots, that actually do damage or knock someone down.
There are more than a few guys who have used body shots well, Junior Dos Santos, BJ Penn, KJ Noons, Nog, Cain V, Anderson, etc..... As for knocking someone down, the only one that comes to mind is Pete Sell, right before he got KO'd by Smith. Further, you dont see that many body shot knockdowns in boxing either, much more common than MMA obviously. But MMA fighters tend to attack the body more with kicks and knees than they do punches. By no means does that mean MMA fighters dont know how to throw a proper body shot, many of them certainly do. They just choose to abandon body punching when they fight, why i am not sure. Let's not try to compare the hands of an elite boxer with MMA fighters, there not comparable. But that does not mean MMA guys cant or dont know how to use a technique (though for many that is the case) they just choose not to. MMA fighters have allot of offensive tools to work with, so it makes it far easier to overlook the effectiveness of any 1 particular skill..........
You also have to realize that throwing a body shot in MMA is a bit riskier with the 4oz gloves. Boxers often go to the body and know they may take a counter shot up top, but boxing often is more a war of attrition and boxers know that banging the body will give them a more vulnerable opponent in the later rounds and that risk is worth taking a shot or two up high. In MMA, with 4oz gloves it does not take as much to really hurt a guy, or cut a guy up. So throwing a body shot is a bit riskier a proposition.
Body shots don't always appear to cause immediate damage, but they do and the more you take the more it takes out of your opponent. It is a common misconception that head shots cause more damage, they do cause more visible damage. But getting hit in the head doesn't cause near the cumulative damage that getting hit in the body does. Yes, head shots end fights by knocking someone unconscious! no secret there. But a shot in the head is easier to shake off and recover from than one in the body. I would much rather take a shot in face that still left me standing, than a shot in the liver....... cause that shit will haunt you for the entire damn fight!