My thinking about why small calibers were so popular 100 years ago is because people were much more worried about getting shot, period, by anything, as their were no ambulances available by dialing 911, and what would be a minor wound today could be a deadly wound back then.  So there was the fear factor--people, even miscreants--seemed more likely to comply with orders issued at the point of a gun, any gun back then than they are today. 

Today, half the time the criminal thug is drugged-up or drunk, so at least not thinking straight, maybe not impressed by a small gun, especially if the gun wielder doesn't appear to be in control of the gun they are holding, heck they might not even see the gun if they are too far gone.  Or perhaps they've been shot before--many of today's thugs are recidivists--and they know they can survive most handgun rounds, especially if their intended victim is shaky and appears not able to hit the broad side of a barn.  Anyone who is well read of this topic today knows that a .22, .25, and other small rounds, whiile certainly capable of killing, are not usually capable of rapidly STOPPING the bad guy from continuing to harm you or your loved ones.  We have learned our lessons in the last forty or more years in the USA.

(Yeah, it took other countries longer than us to stop issuing .32s and .380s to their COPS...)

By the way, my son used to collect cartridges, and has a 4.25mmLilliput round in hiis collection.  Makes a .22 Short look like a manstopper.