None of this is relevant for the scenario you originally proposed and what I was commenting on.

When a car is totaled, there is no argument for diminished value, since you are given the full pre-accident value of the car.

Your points are valid for some cases (albeit so rare that you found an article from over a decade ago about a single case that made the national news, in a province that has since had several major overhauls to their insurance regs.), but have nothing to do with your prior argument or the comments I made.

Leave the goalposts where you originally had them.

My point with the news article isn’t about the diminished value, it’s just an example of insurance companies willing to spend money on lawyers and appeals to avoid paying out what they don’t want to.

I’d expect any insurance company to ballbark the “full pre-accident value” towards the lower end of comparables, and while you might be able to negotiate that up, you’re never going to be able to recoupe everything you’ve spent on a highly-maintained car, because a lot of that simply has minimal effect on the resellable value of the car, or won’t be provable value - e.g. you can spend $1500 on top-end UV-protectant window film, but that’s pretty much never money you’ll get back in a sale or insurance claim.