Except that a bigger round will always do more damage. The recoil in a .45 ACP is negligible, the mag capacity difference is usually four rounds or less, and people handle stress differently, then you might be right.
Take the same designed rounds in both calibers and the .45 ACP will do more damage. Why? It is a larger round, moving slower in most cases, and causes more trauma. Physics. Recoil is not large and a null point with proper training.
And higher velocity to me is not a good thing, over penetration. I want my rounds to hit target and take their time going through, or not going through at all.
And saying it would have taken just as many shots with one caliber as the next is wrong, period. Shot placement is important, but again, a larger foreign object entering your body is going to do more damage than a smaller one. Giving more room for error in shot placement. A .22 will never create as much trauma as a .45 of the same design. Speaking in pistol calibers here.
And some rifle loads, 5.56, are basically ineffective at certain ranges and rifle barrel lengths. Anything 20 inches or less usually. And a pistol caliber round would out perform the rifle rounds in shorter barrels or close range.
And as far as training, I think that is also largely dependent on the person. In a combat or high stress environment, I assure you. I personally will have no trouble. As I don't let little things get to me. But most people would. I agree, without training.