Not that this is my motivation for not firing a gun, but right now quality firearms are considered the best investment commodity behind the precious metals. The return on some of the ones you mentioned can be higher but they come with a lot more risk than guns and once a gun has been fired, you can use it to your heart's content and clean it back up without devaluing it.
I actually bought both guns with the knowledge that they were in mint condition and did not expect them to be unfired. The S&W-trained gunsmith to whom I have my Internet purchases shipped inspects them for me and is the person who pronounced them unfired. I prefer not to buy unfired specimens because I will be hesitant to shoot them and they usually cost significantly more, especially if they come with their box and its contents.
I have several 6" 686s that I shoot so not firing one or two is not a big deal. I bought that Classic Hunter because there only are 5,000 of them in the world and the last two were shipped in 1994, almost 20 years ago, so some have been mistreated, modified or lost. Couple that with it being a Smith & Wesson revolver with forged parts, no lock, a square butt and a grooved grip frame (all things no current-production S&W revolver like it offers) and the unfired part becomes icing on what could one day be a valuable cake.
The same goes for the PowerPort only it unfortunately has a round butt. But it also is out of production, so it could have a similar appreciation future. But then, my crystal ball broke years ago...
Ed