The same arguments you make for the Sig round were stated abundantly about the 10mm ... And yet it's an also-ran in terms of selection.
The bottle neck effect of .357Sig may help in some cases, but I'd contend that's a band-aid to a poorly designed or made feed ramp. 9mm feeds just fine in well made guns. Stoppages are typically a result of a poor fit, and/or a poorly designed bullet nose. The case shape, itself, should not be the reason a round does or does not feed. In fact, the case really should be the second thing to hit the ramp, not the first. The bullet is the main reason a round gets where it's desired. Nose shape, ramp angle, magazine grip on the case, etc all play into this. That bottle neck shape is secondary to a good bullet/ramp relationship.
As for velocity, I'll counter with this ...
Group-think, as you call it, is changing most of the time; it evolves. The "old" group-think was that speed is king; hot and fast was were it was at. And so the 10mm and .357Sig were developed.
But real world data shows those rounds, when fully loaded, don't put a person down with any more efficiency than a well selected .45 or 9mm. You can yabut this to death (yeah, but ....) and it won't change real world shooting data. Speed does NOT equate to lethality in human targets. Very fast rounds have a tendency to over-penetrate (exit). Anytime something exits, it means energy that should have been dumped into the target is actually being carried out of the target and into a secondary target (hopefully not an innocent person in the background). If your round starts with more energy, but it leaves only X% in the target and carries Y% out, then you paid for energy you wasted.
And again, the hotter and faster the round, the more sound and flash you'll get, too. Ever fire a gun in a home? I have, and it was terrible. It would only be worse if it were louder and brighter. If I need follow up shots, I need to see and not be blinded by residual retinal flash effects. I might need to be able to hear someone behind me, and the least amount of ear-ringing is the most desirable. Any time you fire a firearm in an enclosed area, it's bad. But it's worse with hot, fast rounds. Also, hot and fast also makes follow up shots that much more difficult, and (when fractions of seconds may count), slower.
The .357Sig was basically created to make an auto-loader duplicate the size/speed of the old .357mag. The 357mag had a great record of being effective for decades because it was predominant in LE use, and contrasted to other choices like .38spl, it was king. But we all know the .38spl was just a poor round for lethality, overall. So the "dominance" of the .357mag was mainly due to it being a high-spot in an otherwise poor choice arena. The .357Sig was made to duplicate the .357mag's effect, by copying it's speed and size. But that lethality data was based on decades old info. If you took today's well made 9mm, correctly applied in the right barrels, it is just as effective. The point is that the .357mag wasn't really so awesome because it did things well; it was awesome because it had relatively little viable competition. The 357Sig did exactly what it was designed to do; it's fast and hot and the same size as it's namesake. The .357Sig duplicates the characteristics of the .357mag; fine. But those characteristics don't mean it's any more effective than a well done 9mm. There was a time when 9mm rounds were not effective; those times are past. The technology of design, quality of propellant manufacture, etc all make the 9mm today every bit as good as .357 choices.
I am not saying that we cannot appreciate the vast majority of calibers we can have. I own a LOT in my vault, and love the variety. But what I have for fun, versus what I need in times of SHTF, at two different things. Again, for human targets, we need accuracy and stopping effectiveness.
Yes - the .357Sig will be around for a long time. As will the 10mm. Both lurking in the corners of niche production because in full power, they have compromises that cannot justify their use most of the time. They never were, nor will they ever be, mainstream.
Some of you might think I've always been a 9mm man. That's not true. For years my personal carry was a Glk29 in 10mm. I, too, used to be under the impression that speed and size mattered most. But then I started to look into the real world data; not gun magazine bench racing. And the reality is that these two things are really most important:
1) get it on target, every time
2) dump all the energy in the target, and expend none of it on exit
Really hot, fast rounds have a propensity to make both more difficult.
I wholly agree this is a personal choice; no problem with anyone carrying anything that they can safely handle.
There are times when we can all bring into the conversation a "what about this" example.
- We had one a few years ago in our neighboring agency. They had a police action shooting where they had to dump several rounds into a teenage kid; more than a dozen as I recall. All 9mm. Some questioned if the 9mm was too weak. The kid was not even doped up; well not with illicit drugs anyway. He was amp'd up on his own adrenaline! There is a condition called ED (excited delirium) that makes people almost "super human" in terms of strength and fight from their own body chemistry. Shooting that kid with hotter, faster bullets would have only made more of them end up in the car behind him.
- We had another one a county over where one shot from one 9mm killed a person almost instantly.
There is no "perfect" round. There will always be compromises. There will always be some contributing condition that makes someone want to coach it over again from the couch.
But the real world data shows that fast and large do not show any correlation to more kills in terms of efficiency. Fast and large rounds may have a minimal contribution, but they are dwarfed in massive fashion by putting rounds where they belong, and not wasting energy outside the target. Fast and large are just noise in the statistical data of macro-data shootings. Like I said before, the data does not show they are "better", but the data does show that neither are better.
If anyone has real shooting data that would contradict this, please show me. I'm not adverse to learning from new sources. But it must be credible; real shots on target, not gun mag hype.
The feeding advantage of .357 SIG is merely incidental to its bottleneck design; not some band-aid afterthought that was applied to correct any deficiency in feed ramp design or anything like that. It's just a fact. All else being equal, a bottleneck round is going to have an advantage in feeding.
You argue that a projectile's higher velocity and its resulting greater energy dumped on-target (in this case, .357 SIG vs. 9mm, .40 or .45) doesn't stop a human threat any better than a slower projectile. That's simply untrue. If that were the case, there would be no need for rifles or anything more powerful than 9mm pistols. The facts are that higher velocity and energy transferred to a threat equate to greater damage, and a higher likelihood of stopping an individual's threatening behavior immediately. It's just physics. The more damage a bullet is capable of doing, the higher the chance of causing the kind of damage that's necessary to stop an attacker in his tracks (interruption of CNS function through damage to brain, spine, or other major nerves, or immediate, massive loss of blood pressure, or destruction of major, load-bearing bones).
As far as overpenetration, you're wrong on that as well. It's common knowledge that, at least, with the best-designed modern bullets (HST, Gold Dot, PDX-1) that expand reliably regardless of clothing, etc, higher velocity DOES NOT equate to overpenetration. In fact, it's the opposite - higher velocity translates to greater expansion of hollowpoint rounds, and LESS penetration.
Here are 4 videos by respected YouTube ballistics tester tnoutdoors9 showing this:
.357 SIG HST (13"):
.357 SIG Gold Dot (14.5"):
.357 SIG PDX-1 (12"):
.357 SIG Gold Dot (loaded by Underwood Ammuntion to 1500+ FPS from 4" Glock 32 barrel)(15")
So, the above hollowpoint rounds are considered by some (myself included) to be the best available defensive hollowpoint rounds available on the market today. And, with .357 SIG, they all fell within the 12"-16" range deemed acceptable by the FBI. These rounds (I personally carry the Underwood loading of the Gold Dot in my G32) dump the entire 600 lbs. of muzzle energy into the target.
And, as far as accurately getting rounds on-target, you are right that there is more recoil than the typical 9mm, and that it will be too much for some, especially those who don't shoot much. Personally, I go to the range and shoot a lot, and most of my handguns are big-bore. I'm over 6' tall, have large hands, and I'm not recoil-averse (my first handgun, bought over 15 years ago, was a Glock 20). Plus, I don't find the recoil of the Glock 32 to be hard to handle, at all. It's about the same as an average .40 S&W.
So, it boils down to an individual choice. If you believe you're fine with 9mm, more power to you. I have no problem with 9mm. In fact, it's my EDC most of the time (Sig P938 loaded with Underwood Gold Dot 124g +P). Just don't try to tell me that a higher-powered projectile is no better at stopping a deadly threat than a low-powered one.