I suppose the answer is rarity. This is most likely the only time someone would get the chance to own a #/5 snare drum, that could continue to gain value as they will never be made again.The market sets the price. As I mentioned, the silver diamond snare went for 5000-6000 US, and those are significantly less rare.
Rarity often doesn't equal $$$. This is a common myth. You're right, the market does set the outcome...which is why its been dropped by 50%. The market changes.
I have to agree with others, who the hell would pay that amount for a snare. To each their own, but its absolutely silly, imo.