If your premise is true, it's a no-brainer. Buy the used amp. Who knows, if you don't like it, maybe you can sell it for $20k. I've had great luck with used amps. My Adcom 555 is much older than 10 years, and still performs very well. Same for my PrimaLuna. Amp technology hasn't changed all that much over the years.
Buy a $40,000 10 year old amp for $4,000 or new amp for same money?
Hi. There are bargains to be had on really high-end components that are more than a few years old. DACs change too much and we need the newer technology. How about amps and pre-amps? I know it can depend on the specific amp but in general is a 10 year old amp that was $40,000 in 2009 and now sell for $4,000 a better value than a new amp that sells for $4,000 in 2019? How much has amplification evolved in the past decade or so? (I posted a similar questions about speakers in that forum). Thanks for all the input and wisdom.