Very good sounding modestly priced products continuously undercut the value of the uber expensive "high end" gear. Fewer and fewer people want that big heavy high price tag stuff even if they could have it for an affordable price. But those who spent big bucks on expensive new gear do not want to take a loss. There are more very good sounding affordable and practical commodity items these days than ever before starting with a smart phone with streaming app and headphones that most already have and on up. Greatly beats the transistor radio, portable cassette player, and stereo phonograph that I started with as a kid for sound quality.
Also when buying used the buyer assumes a fair amount of risk when buying expensive items. Many things can go wrong that seriously undercut the value of what one buys used and repairs may take forever and be quite expensive as well. A money pit! Better off buying through a reliable intermediary who will certify and support used gear bought for some period of time initially.