As someone who buys, sells, and trades a lot on other forums, just my 2 cents.
Location is always a large part of a sale of any tool like this that can't feasibly be shipped. For instance, I emit a particular pheromone that turns off the selling-stuff synapses in the brains of fellow woodworkers, and causes no good deals to be posted within a two hour radius of my house. Sorry to anyone else in the middle of the Piedmont.
This is an item of relatively limited appeal- not that it is a bad tool or a high price, but rather that most people and therefore most of the audience would probably not personally purchase a drum sander. It is of course a very useful item- but it is also one that takes a good deal of floor space, requires some specialty supplies to be kept on hand, and simply won't be used often enough to justify those inconveniences for most people. For myself on the rare occasions I needed a drum sander badly enough to really consider it, I took it to a professional who had a very large one to run for a very reasonable price. Although inconvenient, the nexus of value and rarity that I need one balances in favor of "farming it out".
Hobby size tools like this also get a double whammy in that a professional is likely to buy a much larger one, and an amateur is likely to not buy one at all or take it out to a professional to do on his monster machine. Most amateurs are working out of their garage or maybe a wired workshop- a hobby grade tool that commands considerable floorspace and is of infrequent usefulness would be a difficult sell for the average amateur, and not heavy duty enough for most pros.
This is also not a massively heavily trafficked forum, and therefore the exposure is not tremendous. The handful of sales and purchases this site facilitated for me as an amateur woodworker but professional tool aggregator have been nothing but perfect, but this is not a site that receives gigantic amounts of traffic. Most items that can't be shipped do sit here for a while unless they are in extraordinarily high demand or are a truly phenomenal deal. I know I bought a good quantity of lumber at an excellent price from another member recently who lamented how long his ad sat unanswered, although the lumber was good quantity and the price was around a third of what I would pay commercially.
Given your asking price includes several extras and is still around half of the new MSRP, I think the price is fair, it's just a limited market even among woodworkers. But many of us are also very cheap, and often used woodworking tools do go for half or less of their MSRP.