The reality is...
These calibre wars have been going on for some time, and will continue in the future.
This "one-shot-stop" business will as well. And not just for personal protection, also in the realm of hunting.
The old suggested ideas remain the same:
Carry/use the largest gun one can effectively get quick hits with. Oh, and very important, one must be able to not only effectively carry the firearm, also be able to access it.
It does no good to have a firearm, and its loading, if one cannot carry/use it, and get quick effective hits.
There is a reason it is suggested, and I personally know many THR members, including Staff, that the home guns, are guns the "smallest" person in the home/office can effectively get quick hits with.
People change, just as environments.
I believe it is Mr. Hackathorn ( correct me if need), that suggests one take a sheet of typing paper, fold in half, then fold again.
Set this target at 5 yards, and only load 5 rounds into the handgun.
At the "go" (timer, stopwatch, whatever) shoot as quickly and as effectively to get good hits.
This will determine:
-What gun fits you. Semi-Auto, or Revolver, Make, Model and whatnot.
-What caliber, and what loading in said caliber fits you best.
This. Will. Change.
i.e. Retired law enforcement officer that carried a .357 magnum, with .357 magnum loads, and back in his day, qualifications included shooting at 50 yards.
Not feet, yards.
Arthritis and other age crept up, so using the drill mentioned above, he went to Standard Pressure, 158 gr, LSWC-HP.
(Lead semi wadcutters, hollow point).
He could get NOT get quick effective hits, with the .357 load.
His health went down, including hip replacement. He could not wear the heavier revolver, as he once had, and shot the drill again, and this time, went to using a Colt Detective Special, using 158 grain LSWC.
His hands got worse, and some days used 148 grain target wadcutters.
He did NOT default to gun, to solve all problems. Instead he used his brain.
e.g. Having the drug store deliver prescriptions, instead of going out for the Rx.
Asking someone to go with him, when he had errands to run, like bank, post office, and doctor's office.
Animals do not know how they are supposed to react to a make, model of firearm, or the loading.
Human beings do not either.
Some humans, freak out, just from the sight of a gun, the sound of a gunshot, or the sight of blood, and the like.
Some humans, do not.
Many a animal being hunted "did not drop right there" and many humans have shared, they had not been aware, they had been shot, until it was pointed out to them.
One shot stops are marketing tools.
Ninety percent of fishing gear, is NOT to catch fish, instead to catch fisherpersonss wallets.
I was mentored to not get into a situation in the first place, and to evade if evil showed, and then deal with the threat, if I could not evade, until the threat was stopped.
Until the threat was stopped, is the key, no matter what make, model of firearm, or its loading.
No matter what make model of cane, car antenna, bottle of water, rolled up newspaper/magazine, ink pen, number two pencil, pool cue, pitcher of beer, pizza pan...