Real Estate, Stocks and Bonds, Precious Metals, etc. all seem to me to resemble "Investments"
For me, guns are like gambling. I don't put any money into guns that I cannot afford to lose.

I find the experiential aspect of firearms to be key when considering value.
How do you put a price on the time you've spent and the friendships you've built in and around guns?
We all drive cars. The diminished value of these "things" at the end of their useful life is generally accepted without the blink of an eye.
What makes guns so holy?

When I've reached the end of my useful life, I expect to look back and smile at the time and money I've spent on guns.