This idea that the caliber is going to make much, if any, difference in the outcome of most situations is just silly.
Remember David I'm simply trying to select in advance a weapon/caliber combination that provides me the attributes that best serve my expected purpose.
If I expect a greater need for penetration then caliber certainly does matter. If I expected a wave attack caliber would also matter.
Take your 10/22 or AR in 223 and try to reach the BG's shooting from behind a vehicle or a block fence or even a dumpster. Yeah I know you are so good that you'll hit them in the head when they pop out to fire right. Well I'm good also.....better than most......I'm also realistic. The pressure of a shootout combined with the erratic movement of the BG's will surely spoil my aim. Same reason we are taught to shoot for COM if I had a rifle chambered in a caliber that could penetrate alot of cover I could increase the size of my target and thus my chances for survival.
These are the reasons I feel caliber matters. It may not matter much but it certainly matters. When you have done just about everything you can to ensure your survival....even the small advantages could be huge.