great OP. it's the time of the year for one thing. I see the thread started in July, summer sales are slow. from June until December, not a good time to sell actually. January until May is the hot months to sell.
another thing is this, I have tons of stereo equipment from a side Ebay business, mid-fi and consumer-grade, but some nice stuff regardless. but my kid wants nothing to do with it. I offered to put together a system for his apartment for free, and donate it to him- he doesn't even want it. they listen to music on their phones. the only true stereo they hear is in their cars or trucks while driving, it actually has a balance and fade knob.
the industry started off with mono, evolved into stereo, then quad, then surround, and now has devolved back into mono from a tiny phone speaker. IMHO a phone sounds inferior to a good tube amped 1950's mono RCA record player using a shellac 78rpm record. (those actually sound really good, very realistic albeit mono).
the big corporations have pulled it off, they managed to charge $600 for a handheld audio device that is mono, and they got it.
stereo won't die immediately- it will fade like Elvis' record catalog. still popular, still well known, but will sell fewer and fewer copies as time marches on.
having said all this, there's nothing like a good mellow sounding single ended pentode amp through 2 decent speakers, once it's warmed up- it does everything good and a few things really great. kids today don't have the time or inclination or money to investigate these things.
