There was a company called DAK in the 80's that sold all sorts of interesting stuff and I still use my BSR EQ-3000 which is an equalizer with a spectrum analyzer display fed by a microphone that you walk around the room with to confirm your settings. It even has a pink noise button that injects that into the amp so you have a uniform pattern to equalize. Sort of like an analog Sonos Trueplay I guess. We could do all of this in the 80s :-)

I suspect HiFi culture was slightly different in different parts of the world.

In my part of the world, the original HiFi guys rejected the EQ units. I was influenced by that I think (my father was an original). I still have a metre high stack of HiFi, in almost daily use, and have never felt the need to have an EQ unit.

I built my own 10 band equaliser using instructions from Elektor (I think) back in the 80s. The dream was to acquire a spectrum analyser but real life intervened.

Not sure when I even powered up my stereo system. Probably doesn't even work now.