What's wrong with 9mm? Service/duty handgun calibers are poor at incapacitating individuals unless you shoot them in the CNS, and even that isn't a guarantee. Ball ammo, whether it's 9mm, .40 S&W, .45 ACP, etc., is a poor choice of ammo, so switching to a larger caliber really only affords you less ammo, more expensive ammo, and a heavier recoiling weapon. 9mm is the more logical choice for a large armed force (mil, LE). Modern hollowpoint technology has bridged the gap between the common service calibers, unfortunately the military proper doesn't use them.
As an individual, carrying any of the aforementioned calibers in a modern hollowpoint works, but it still doesn't change the fact that a larger caliber bullet provides less capacity, is more costly, and is generally harder to shoot for most people. https://soldiersystems.net/2014/09/25/fbi-9mm-justification-fbi-training-division/