@daveyf
Again, to beat the dead horse a little more, I have successfully bought and sold several items this year. Both types of transactions were pretty quick, less than 1 week typically soup to nuts. I've sold some NOS tubes that went quickly for my asking price, several cables, accessories, etc all went for what I considered good prices to fellow Audiogoners both young and old. I sold some speakers that listed new for just north of $20,000 for just north of $10k. They were 3 years old and in excellent condition. I've purchased some gear both here (gently preowned) and from dealers new/demo.
Respectfully, your friend selling cables for 10% of list indicates they are not very well thought of by the audio community at large...new or used. I have a pair of Transparent Gen 5 Reference speaker cables at home and Auditorium 23 speaker cables in my office and the latest Transparent cables would probably sell for 50-60% of list fairly easily and the A23's probably 80% of list. So, if something sold for 10% of list.....they were probably not that good were they? In other words, scarcity and perceived quality drive any commodity's demand and value. You must use a better example than "your nameless friend sold some unnamed cables for 10% of list so therefore the hobby is going to shyte". That is an uncorrelated data point and unfair to the community. The sky isn't falling.