The fact you aint sold it yet is argument enough
heh...
(Must be nice to feel validation so easily.)
if selling an item within a 3 day listing is the test then you'd have to say 90% aren't priced or listed correctly.
20-30% of items I've listed didn't sell the first time I listed them or placed ads elsewhere.
Just giving people a chance to look at something doesn't mean they need it or that the right person sees it.
My usual method is to attempt relisting and if an item still doesn't sell to combine it with other items (i.e. install it in a machine to raise it's value, etc.)
Buying used equipment requires research and knowing what you want and what you're willing to pay. Selling requires finding the right person who wants what you have. It has nothing to do with the myriad of folks willing to kibbutz about what they think about your item, who have no intention of bidding, offering or buying.