"Desirable" is a very important modifier here. A generic Rem700/Win70,or all the glocks and glock clones out there etc don't increase in value (or even hold their original value) by simple virtue of age or having successfully sent rounds downrange without exploding.
Unless it has historical value, or is rare etc. it's just a tool... using it decreases the remaining useful life and the price decreases accordingly. Simple math.
Can't dispute a word you wrote and my perspective is that EVERYTHING that ANYONE has EVER owned (WRT firearms in general) has GREATLY increased in value by virtue of the fact that "THIS," (insert your preferred gun) isn't made any more or has been superseded by the next generation and THAT means THIS version is unique enough to warrant a pricing structure that is WELL above typical and normal for THAT gun!"
(Emphasis mine to make a point on how some folks feel, but it's mostly in jest. Mostly.)
When politicians are in session and anti-gun legislation is pending or up for discussion, it becomes a nightmare and percieved calamity to the gun buying public.
Panic sets in, gun sellers can sense and smell the blood in the water (metaphorically speaking) and the prices of the most obscure doo dad SKYROCKET to absolutely INSANE prices!!!
And here's the worst part.....
PEOPLE WILL PANIC BUY AT THE MERE MENTION OF A PENDING BAN OR RESTRICTIONS on ANYTHING!!
Witness the scare of .22 LR/9mm/.40S&W/.223/5.56 ammo and how other posters pointed out the continued marketing of .22LR bricks some Sad Sack bought during the panic and how they DAM*ED SURE ain't gonna sell that brick for less than what HE paid for it, much less his markup for profit!
WRT those seriously overpriced bricks of .22LR ammo, those guys are PRECISELY the ones I will literally LOL in front of them because they are nothing more than "War Profiteers," IMHO.
I understand Capitalism and don't begrudge making a profit but those types are of the notion of stripping a still-warm body and selling everything while the body is still warm AND while the poor guy's family were standing right there!
NOT COOL!!
All that said, used and REASONABLE prices for a reasonable gun are gone, I fear.
I've always said that should I decide to sell my firearms (the ones that didn't fall into the ocean from my overturned canoe you understand. HAH!) then I could make a darned pretty penny and live comfortably. I just cannot bring myself to screw people over. It just isn't in my nature.
But I need to start seriously thinking about selling the bulk of them (notwithstanding the canoe accident) as I'm not getting any younger and I might as well enjoy spending MY money as opposed to someone else selling them for FAR less than what would be reasonable prices.
Time to shaddup for now.
Thanks for putting up with the rants of an old Curmudgeon.
Overnout