Mep, this is often the case, but I have sold cartridges and amplifiers for more that I have paid for them. And some classic products reach a price and then do not depreciate much further. Some even go up in price. It all depends on what the market is and what one paid for the gear. How long you have the gear also matters. I know one owner of the Q3 who thinks they will actually go up in value based on used prices today.
Brodricj suggested getting a used pair of Q3s. I paid $17K for mine and there are two for sale now around $25K. Yes, speakers do take a big hit, but if you buy right, and the speaker is in demand, you may not lose much money. Brodricj did write "...then sell Q3 for about what you paid for them." The key is "for about". I think Brodricj is right on this one. I could sell my pair of Q3s tomorrow to a guy I now who is looking for a good pair for $20K. That's how that works.