There's a Warhol print, for instance, that's been on Ebay for over a year. Even if it never sells, it makes money for the dealer: Some percentage of the people who see it also look at his other items and end up buying a $100 Peter Max poster or an $8000 Keith Haring print or something.
Interestingly, the dealer keeps tweaking the Warhol's auction text. Every couple weeks, he changes something -- the title, the subtitle, a few words in the description, even the shipping terms -- as though he actually expects to find the magic phrasing that'll induce someone to mail him $100K+.