I carry a snub, (or a .380 LCP) most of the time and don't feel "undergunned".
As others have said, if a fight started, I'd probably feel undergunned if I had an AK.
I've seen police dashcam videos where an officer emptied his hi-cap auto at contact distance
and missed every shot.
Higher ammo capacity may give you a survival edge, or it may not.
In any of those situations, I bet the officer would have rather had one hit than 15 misses.
As the old saying goes, "You can't miss fast enough to win the fight.".
I practice with all my guns, and I'm probably a better shot than most thugs I may encounter.
Still, there's a better chance I'll need O.C. spray than a gun.
(Still haven't gotten around to carrying it all the time.)
When I only had larger guns, I usually left them at home.
I'd rather have 5 accurate shots in my pocket than 15 shots at home, or in the truck.
Years ago, I had just gotten my CCW permit, and was at the range/gunstore for some practice.
There was a younger guy in the lane next to me with a large auto, and a large new shoulder holster.
I wondered then if he would ever wear that rig for an actual day out.
(Here in East Tennessee, we only get below 40 degrees 2 months out of the year.)
I've got a shoulder holster too, and I think I've worn it once in 15 years.
Carry whatever meets your comfort level, and hope you never have to use it.