I'd have to agree that the selling of flea market type items has become too much a part of the gunshow.
That is what sells, so they have it for sale.
Max you can draw out of an ATM is $400, $100 for beer, so they have 300. They walk the show looking for something free but if not given something then they buy crap as a token that they were there. My mouth dropped as I saw it over and over and over again.
I rented tables in November 2018. It was a wonderful education. Guy behind me had fidget spinners and he sold out by Saturday afternoon and walked away.
I experienced it myself when I brought the collector grade stuff out of the safes. Nothing. Couple of older guys stopped to tell that they "used to have that gun" and then walked on. I put out the schmaltzy engraved knives that I got from like FNRA dinners or Smith & Wesson grips and there was a feeding frenzy. Crap sells, that is why it is there.
Usually I am a List Guy. The guy in the khakis with the half reading glasses and the checklist with the oversized messenger bag? Yeah, that's me. It was not until I rented tables that I learned why gun shows are flea markets now.