Destructive power is wasted when it's a miss. And hitting an area with little ability to soak up the power imparted means its about the same as a miss.
People have been hit with 8mm Mauser, .50 BMG, etc etc and all the destructive power did no good. They fought on and defeated the enemy shooting at them. Shot placement is critical, not power. Some took multiple hits with large caliber rounds and it did not stop them. They were not placed adequately.
One hit to the right component, tho, even if it's a .22, and they could be killed. The fallacy is thinking that high amounts of power are needed. The reality is that military small arms have been downsizing calibers for the last 100 years.
It's not about power, it's about hits. Smaller caliber, less recoil, more ammo, more hits. If you missed or inadequately hit the first time, shoot again. You can't do that when limited to a finite number of pounds of ammo and it's all large caliber, you run out. With smaller cartridges you are less likely to at the point where you exercise dominance on that battlefield.
That's what the Battle Staffs of most modern armies in the last 100 years have decided, and being their professional opinion I tend to give them some credit. They made anything larger than 7.62 x 39 obsolete. And they made that obsolete, too. The standard caliber for small arms in the world's armies is something smaller than .30, it's the civilian shooters mired in tradition and extreme conservatism who are stuck on them.