I can see why the vintage crowd kinda gravitates to EQ when putting their system together. Pretty much the same reason people shopping for "Home" audio 40 years ago. It looked cool, it made them look like they knew what they where doing in front off friends, it made the system look bigger and better, this is a professional system your looking at buddy. The manufacturers did the same thing, "look at our rack system, professional grade!!" and then they liked the fact it's more they can sell to the buyer.
Did anyone ever notice that during say the 60s....no EQ, except for the phono.
How about a lot of the 70s, when receivers where big and in wood boxes, was there any stand alone EQ built in a wood case to go with your receiver, tuner and integrate...Nope no EQ
Then all of a sudden the rack mount gear showed up

, a roll around cabinet, separates, EQ, rack mounting R2R.......Reverb...Strobes...Audio Mixers... The Manufacturers loved it since Quad took a dump and they couldn't sell the idiots a bunch of supporting gear for it. Hey lets build a bunch of crap that looks professional and they will buy it....idiots

95% of those buyer didn't know how to use half that crap and still don't....
McIntosh has a Room correction component, that you run a sequence with a microphone and the computer sets parameters for the system in that room. With that said please do tell me one high end manufacturer that sells a EQ with their system today....none!!!!
So either the equipment suck so bad in the late 70s and 80s one needed a EQ
Or the music sucked so bad in the late 70s and 80s one needed a EQ
Or the rooms sucked so bad in the late 70s and 80s one needed a EQ
The one constant I can think of.... the same idiots are around