Well, sometimes it works out. Back in the early days of ebay, I got me a digital camera and started selling on ebay. There was a local folk instrument repair guy in town who was able to acquire lots of very cool used (sometimes vintage) guitars, banjos and mandolins, and I would sell his instruments for him on ebay for a small fee.
(store was The Folklore center in Prescott AZ)
One time I sold a pretty cool newer Gretsch acoustic guitar for the store. UPS promptly knocked the box over during shipping and cracked the neck. The guitar came back to me after the seller rejected it, I filed a claim, got paid in full for the guitar. I paid off the seller and got to keep the guitar. I glued and clamped the crack, it worked fine. Free guitar! Plus I got the selling commission from the music shop owner.
I think if you are a casual seller, one or two sets every couple of years (maybe less?), you aren’t going to want to ship. It’s the real wheelers and dealers who want to spend that time and take the chance. I’d much rather go to Rochester Drum Trade (or wherever) and get a fair trade or some quick cash and be done with it. I spent some time packing and shipping in the past and those are hours lost!