You have a good point, in theory. I know I may be an oddball here, but here is what I do. Now for full disclosure, I am an officer in a small town, with limited resources, and all equipment except the vehicle is personally provided. My primary handguns are .357 Mag, .40 S&W, and .45 ACP, my rifles are .223 and .308, and shotguns are 12ga and 20ga. What goes with me depends on the plan that day. Standard is the .45 on my hip, the .357 as backup in my pocket, and the .40 in my bail out bag, with the 12ga Mossberg 500 and .308 FAL as my primary long guns. The .223 is a suppressed SBR and sees very little use except when serving warrants on meth labs due to the suppressor decreasing the likelihood of igniting flammable gasses and blowing the place up if any shots are fired. So I carry, use, and trust all the above pistol calibers, but definitely prefer the .45 and .357.
Now being in a small town with just one of us being on duty at a time, my backup is at least half an hour away, and often an hour or more, and that is IF I have radio or cell phone reception to even call for help. So really, my main advantage on duty is my vest, which is of limited utility in a rural area with most vehicles having deer rifles instead of handguns. So there's really not much difference between me on and off duty, or me now vs before I had a badge. We provide our own weapons and ammo at my department, so duty weapons are also what gets carried off duty. In my case, it's still the same .45 on my hip and the same .357 in my pocket, with the same rifle and shotgun in my vehicle.
I have one officer who carries nothing but a .40 and refuses to keep a long gun. Two who carry 9s, and one of them uses an AR-15 in .223 and the other uses an AK-47 in 7.62x39. It's all in what we each shoot best, but we all keep these things in our vehicles, so still have to rely on our handguns to get to the long guns if needed, just like everyone else.
I know this is different for larger agencies with more resources, but just wanted to give a small town perspective just as a way of saying that the tools each of us carry every day, regardless of if we have a badge or not, are what we depend on, and are really nothing special in the grand scheme of things. But we each need to practice and be able to use them to the best possible effect if needed. I really don't care what anyone carries or how, as long as you all carry something you trust and are proficient with. We can always argue the bigger vs faster vs more rounds vs whatever other argument over a couple cups of coffee while we wait on the lawyers to show up and the criminal to cool down to room temperature. I'm happy as long as it is the good guy who is left standing after an incident.