Is the main reason audio equipment depreciates so much is

can't leave out advertising costs...I'm a cable guy, but $50.000 speaker cables are beyond my understanding...

You must include R&D in the price of a product!

Ji35,

There is no rhyme or reason to it. They just try to get what the market will bare. It doesn't matter what it cost them to make it. They are only Interested in perceived value. 

Jafant,

I read recently where a guy took apart some 20k Transparent cables and try to duplicate them. I don't remember where I read it. So unfortunately I can't provide a link. He wind up buying all the parts and putting it together. He did say some of the parts were a bit different because he could not find all the original parts. Though he said he found many. He says his total parts cost was 800.00. Plus all the time he spent putting it all together. He said at a price saving of nearly 19k he was extactic and he was very pleased with the sound.

Resale is so low because the item wasn't worth near the retail markup it began with, and people on here always want something for nothing.  You don't find that with cars, where dealers are making slim margins. A used vehicle price is much closer to new--too close if there's any extra mileage.