I have gotten some great deals on eBay and here because the seller decided to let me have it for my high bid that was less then the reserve, or still less than I would have offered had it been a classified.
The big auction housed Sotherbys, Christies, etc., hold reserve auctions all the time. If the seller won't sell the Picasso for less than $5 Million, then no sale. The reserve is secret. If they told you the reserve up front, what is the point? They might as well take it to an art dealer and take offers.
When I have used a reserve, it has always been set at the bare minimum I will accept as an offer, if it had been a classified. My reserves have always been exceeded. Probably some people have unrealistic expectations, and set them too high.