I may be getting older (I'm only 65) but I still get urges.
One of the things that makes trading or selling some guns difficult is that you may have bragged about them or waxed poetically about their charms and virtues. It isn't like they have become worn out or need too much maintenance, like an old car. As far as cars go, some people I know don't sell them either. They just get parked in the shed next to the tractor or out behind the barn. That would have happened to our first car, yet another Volvo, which my wife adored. After 18 years we just gave it away. Me, I loved Rovers, which is where "Blue Train" comes from.
Yet another thing is that, like women, you find yourself drawn to most the same guns over and over again. It might seem foolish to trade most of them for something that was pretty much the same as something you already had--unless perhaps it was newer and nicer looking!