Yep just like coin lots there's obviously people out there making lots of the junk they have left over. At least in person you can really check things out, not quite that easy buying online. I too create junk lots from stuff I couldn't be bothered making the time for, but the worthless stuff already went to the trash. I sort of had a good gig several years back that I was buying lots just to create lots, because no one was challenging me on the bidding side, and they were selling very well. But several things killed it so now it's just a junk lot here and there for me now.
Talking about coins at our local auction place...
People will pay crazy amounts of money for coins that are virtually worthless in the coin collecting community. Recently, I watched a guy pay $17 each for uncirculated US sets from the mid 70's. Another guy paid $45 each for badly damaged Morgan dollars, and he bought a total of 20 of them. The coin shop just a few blocks away was selling better date Morgans in nice condition for $28-$30 earlier in the day.