“A lot of stuff the layperson would think is junk is actually valuable.”
I think it’s more often the other way around though - people usually think old stuff is automatically really valuable, simply because it’s old. Or “Rare” makes something valuable.
Trends change, too. Right now, for example, Coleman Lanterns took off pretty high. They all look (pretty much) the same to me, and have for about 100 years. They probably go for $10 or $20 tops in a yard sale. Or ... they did.
Apparently they are recently popular to collect in Japan, and Asia in general. So clean unfired 1950s lanterns say, in the box and with the papers and all the gee gaws might reach $2000 in bidding on that auction site.
It does take a sharp eye and a good knowledge base to separate the wheat from the chaff on that stuff. It’s a lot of work.
Lets not forget something no one talks about on these reality shows.....I’m pretty sure they’re getting paid something by the channel....and I suspect its considerable.