The best thing about this thread is what it seems all of us can agree on: the need for practice/training.
It is fun to have different platforms: Revolvers [da/sa, or sao or dao], DA/SA semi-autos, SA Hammer-fired semi-autos, Striker-fired semi-autos. They all do different things well, and I enjoy using them at the range. I also enjoy different long gun platforms: semi-auto, pump, bolt or lever-actions.
That said, I am in the process of selecting the handguns I will use for a CCW license, and I am leaning toward all of my CCW firearms [we are only allowed 3 on the license] being the same 'platform'. I think that there is some merit in having a single platform for carry, as I do NOT have the time to train with all 4 platform of handguns I own on a regular enough basis to feel confident in MY abilities to perform well under pressure.
That said I am trying to make some things as uniform as possible between the platforms. For example I am trying to make all of the trigger pull weights between 4.5lbs and 5.5lbs for ANY handgun I would use for carry or defensive purposes. I am trying to keep them closer to 5.25 lbs. That way it doesn't matter if it is my Hi Power, my 1911 or a striker-fired pistol: the same amount of pull will fire all of them. For a range/target only gun I don't mind if the trigger is lighter [a race-ready Caspian would be nice with a 3lb pull!], but if I want to have it in a holster I want close to 5lbs and crisp.
I don't see a problem with different platforms. Each platform has its' advantages and disadvantages. All of my handguns can be seen as toys or tools. I have found that the 'one tool for 100 purposes' tools don't seem to do well at any single one of the purposes. I prefer something designed for specific purposes.
I have different vehicles for different purposes. An automatic transmission in the car, a 5 speed manual in the truck, a 5 speed manual on one motorcycle and a 6 speed [ok, 5 speed with overdrive] manual on another motorcycle. I have different drills for different purposes: Corded Impact, Corded regular, Corded torque head, Cordless regular, Cordless right angle. I have multiple saws as well: a table saw, a skill/radial saw, a chop saw, a jig saw and a sabre saw. My dremel tool has multiple attachments.
So I am in the majority on this one: no need to have only one platform.
And we need to train on whatever we may use.
The story of the wife was interesting. I am assuming [dangerous, I know] that she doesn't shoot as much? Some people only want a gun for one reason: defense. Thus they don't see a need to have different platforms. It is too confusing as they don't want to spend as much time training with it.
I have dated some women who had 6 different pairs of shoes with 3" heels, 6 pairs with 4" heels, 6 pairs with 2.5" heels, and then there were the 'wedges' and sandals. I could see the need for one of each at each height, but didn't get the reason for so many versions of each at each height. Until my friend asked me why I 'needed' more than one 9mm pistol....