Of course placement is king but can you do it under stress when someone is firing back?
That's one of the $64,000 questions, isn't it?
Aside from the dynamics of any particular set of circumstances in an unexpected and likely chaotic situation, it may come down to the effort that someone has invested in developing their skillset and practice regimen, as well as their mindset (relative to surviving and prevailing during encounters, even if injured).
If someone can access their skillset and utilize it at the unconscious competence level,
and they have a mindset geared toward survival ...
and Murphy doesn't decide to make an appearance to act against them ... being better skilled and practiced is arguably better than just acquiring some minimal skills and hoping they'll be sufficient for whatever situation comes along. Or carrying some caliber and hoping it will somehow offset a lesser investment in skills and practice.
I've long been a .45ACP aficionado, having carried a couple issued ones (2), and a number of personally-owned .45's (several),
and I like heavier bullet weights, but I've also carried a number of issued .357MAG's, 9's and .40's over the years I carried an active badge and didn't feel inadequately equipped.
I tend to see
caliber as a subset of the
gear component, and not a particularly significant element, overall, at that. I carry more snub .38's, compact & subcompact 9's & .40's than any of my (several) .45's in my retirement. Mostly because of the size & weight. They all still get run through the usual qual courses-of-fire and practice drills to confirm I can still run them, though.
Awareness of the environment and an adequate knowledge base (laws, weapon and tactics) are more important,
to me, than the specific caliber nowadays.
Folks can suit themselves, though, while remembering that every choice comes with potential consequences.
