When I was a kid in the US East and Mid-West during the late 1960's, various kinds of repair shops (electronics, appliances, cars) were everywhere, though only car repair shops persist today. To save money for both themselves and their customers, the proprietors would harvest parts from irreparable gear.
In my neighborhood, the local TV/radio/"Hi-Fi" repair shop was also the rough equivalent of a mashup of today's maker space, a Radio Shack and a flea market (swap meet). Members of the local ham radio club would also hang out there
It was nirvana for aspiring geek-nerds. It was also a total mess, well organized, but not nearly as well as Dave's find. I remember stopping by on my way home from school, to peek over the shoulder of the owner while he was troubleshooting something, then foraging through the bins to find the part he needed. That was what ignited my desire to not only find out how things worked, but to repair and even improve them.
As everything became transistorized, more complex, and made overseas, it also became less repairable, and the lower price made the cost of repair higher than replacing the failed equipment.
One by one the repair shops closed, and most hobbyists had to switch to Heathkit catalog shopping or Radio Shack. But some of the closed shops were moved to the owner's basement, to be reincarnated as a retirement hobby repairing "vintage" or "antique" equipment.
There are still some of these folks around, buying broken equipment on eBay, repairing it, then reselling it. But eventually the original proprietor becomes unable to continue, and the family is left with rooms of equipment and parts to liquidate.
Most often, the inventory is simply discarded, or sold locally though an estate sale. But occasionally a trove will appear on eBay.
Every time I see this kind of thing happen, I remember my youthful afternoons spent at the repair shop, and I mourn their passing.