In addition, it seems to be one of several things:
First, someone may really want an item, and is willing to pay a premium for sentimental reasons.
Like the guy who paid $250 for a model airplane kit that sold for $15 back in the day. It wasn't that great of a kit; I know, I built one. He told me it was because "it reminded him of his dad". Well, O.K...
More prevalent is the "Win at any cost!" mindset. I saw a pair of fellows on daBay (maybe a shill bidder and one other?) get into a feather fight over instructions for making a ghillie suit. The "winning" bidder ended up paying like $25 + postage of $1.25 for 2 poorly-copied pages.
Me? I went to another auction, and bought exactly the same instructions for $2.25, including postage. Still over priced & haven't made the suit yet!
In my neck of the woods, people tend to believe their ooold stuff is worth much more than logic would dictate: Nearly retail. I look, then just shake my head!
But, I figure, if it makes them happy to be happy, then they should go right ahead being happy!