Consider that the stuff from that era was typically hand-made, point-to-point soldered or wire-wrapped. There was a lot more labor cost in the manufacturing in those days.
That said, Realistic brand "hi fi" was never that good, and overpriced for what it was.
I'd be more interested if someone discovered a trove of Heathkit stuff.
In those days I'd buy Heathkit equipment and solder it together :-)
I did that with my H-11 (a PDP-11). It worked perfectly first time, and served me well. It was the only computer of mine I got rid of, and the only one worth any money today.
I had some experience building Heathkits, and the instructions were excellent, so I had no trouble at all with it. I later added a 6Mb hard disk drive to it, building my own I/O card and writing the boot loader for it.
6Mb was oceans of space in those days :-) Now I have an 8Tb drive.
That said, Realistic brand "hi fi" was never that good, and overpriced for what it was.
I'd be more interested if someone discovered a trove of Heathkit stuff.