Unreal prices

Someplace, in storage I still have my mothers old SX750 receiver, her Pioneer PL100 TT. with a Shure cartridge. and Denon (can't remember the model) cassettes player. She also had a pr. of HPM-100 speakers, I think went to my sister.
I never really considered it to be high end audio back then, but it did make a lot of nice music for her.
Not sure what any of that would be worth now, but I sold my vintage Nakamichi ZX-9 cassette player, a few years back and was surprised at how high the bidding went, so who knows what vintage gear might be worth to some....Jim

To miller's point, you see this with a lot of nostalgia items. Price peaks about 30-40 years after introduction, when those who desired them in their youth, finally have the money to buy, and time to enjoy. Then they tend to decline in value as that group of people's health declines, and priorities change. Some true classics will maintain value.

They are way overpriced antiques with mediocre sound good luck to the joker that would pay 5k.

Hi,
Retro is turning into fashion these days and amplified through the net.
At least there is still value in this hobby. You can ask whetever price you want for a good working sample of vintage gear for pleasing the eye and memories. 

The retail of the Pioneer SX-1980 was $1295. In 2021 dollars = $5,660.33. Not a horrible investment if one used it for that number of years.