I mean...if its just "about training", S&W makes a .44 Airweight, why settle for .357?
I do agree to some point that you can 'recoil with the gun' so to speak with some shooting, but that doesn't mitigate enough recoil for most people that are recoil sensitive/adverse, have chronic pain, or arthritis, or maybe just not a lot of strength in general. I'm also not a believer in carrying the biggest stick you can to be most effective, but the biggest stick you can handle and be proficient with. Training can help with part of that, but not all of it if any of the few examples I gave above, or several other potential factors, affect you.
I'm a believer in "the first shot is important", but also being able to get back on target for follow up shots WILL often be necessary in most cases, so yes recoil IS a factor in that as well.
Ive shot some .38 +P loaded pretty hot in a Jframe airweight and it wasn't comfortable at all. Ive shot much heavier calibers that weren't as bad on recoil. I don't like shooting those .38 hot loads but I did often enough to know I was proficient, but generally shot much lighter loads for practice and technique. Guess what I carried? An intermittent load with outstanding performance and moderate recoil that I could control better.
My daily carry is a 9mm, it does everything I expect it to and I can put multiple rounds on target very fast, and I trust the load emphatically. I have and carry .45 ACP when it suits me as well, but not even close to as much. And I wouldn't push anyone to carry .45 just because I think its an amazing caliber, or even 9mm if they cant handle it. And by god you can throw stones at me if you want, but if all you can handle is a .22 LR and you've tried "something more", then I'll back you and won't laugh at you for it. Carry whatever you can carry....just CARRY something!
There are so many factors really it becomes difficult to address them all when figuring out what works for everyone. I think everyone should try shooting different calibers as well as "delivery systems"
to see what works best for them.