I was reading over this thread, didn't read it all but got some of the same feelings as you all. Selling airguns is plenty weird. It's one of the few sales that you pay $2k for a new gun and less than a year later can't get $1100 out of it. So many factors both directions. The gun may still be selling for $1700 and yet a used one will languish for $1100. I've not had any bad luck with people buggering a used gun I bought, been real lucky in that respect. Every gun I have right now is used, in fact I've had few new guns.
One problem, and I can show you a good example in the classifieds, is the value of add ons. There isn't a lot. If the add ons make the used price significantly more than the new price of a used rifle, it's going to take finding that one person who wants it like that. Aftermarket stuff is better sold separately, and even then they lose value much faster than guns do.
I also see a gun, scope, ammo, a compressor, etc bundled. That would almost always take a new shooter to buy. Sell it separately, you'll have better luck.