I doubt that most vendors at a show actually have a brick and mortar shop somewhere. If that's the case, the show is their primary venue.
They stubbornly set their prices not based on the market, but upon their margin and then wonder why nobody buys.
A gun show here (Tulsa) this weekend charges $14 dollars to get in. And once you get in you've got the scenario depicted by the OP. A lot of locals are complaining.
I haven't been to a gun show in several years even though I've bought numerous weapons in that time. I research the internet prices then call the local brick and mortar shops for a reasonable deal.
IMO gun shows are dying.
"I say, boy, I say, you're doing a lot of choppin', but no chips are flyin'."