Seems like inflation and stuff has created a seller's market for good used items of any sort. Trucks, boats, appliances, building materials, furniture, you name it. Seems like anything fairly priced is gone very quickly.
I suspect the popularity of flipping has a lot to do with it as well.
With new trucks hitting $120k for some models, it takes the price of used trucks right up with it.
Since sellers know that most would never spend what they want for a new truck or they don't want to deal with the headaches some of this new junk comes with, the value in a good used truck has doubled or more. I own two diesel pickups, a 1996 F350 4x4 and a 2003 F250 SC 4x4, both have under 20k on the clock. I rarely use them, one is for towing my toys, the other one hauls the camper, which hasn't moved now in a few years. I don't think a week goes by with out someone knocking on the door wanting to know if either is for sale. I don't really need both of them, but both are paid for, and cost me nothing to sit there. My thought is if I had to buy a new one, it would cost me more than double what I'd likely get for either of those two right now. So selling them doesn't make any sense.
The same with my boats, I have four right now, two are identical, only two are registered though. The other two are sort of just spares I guess, but come winter, I lift the spare boats atop the other two and cover them with a tarp. For what they'll save me in tarps over the years it makes no sense to sell them. But I have people banging on the door wanting to buy them.
I also found the best way to sell something is to not list it for sale, they guy who beats on a stranger's door to try and buy something wants it and usually has cash. Unlike most who I've had answer ads lately on FB or CL.
I especially like the guys who run ads saying they buy used boats and motors, but when you tell them you have one for sale, they offer you 1/2 of scrap weight or less.