How much is about the recording

Most people do not realize how bad a recording can be until they hear it on a great system. A good system will make good recordings excellent and bad recordings unlistenable. I love listening to great recordings on a great system as I find myself enjoying artists and music I never considered previously. IMO the recording and the system go hand in hand.

How much is about the recording

It’s everything.

Only a deluded fool believes their system can make a bad recording sound good.

Only a deluded fool believes their system can make a bad recording sound good.

Given enough tools, I'm pretty sure I could make a bad recording at least sound acceptable. But I still agree with what you are saying.

The late Rudy Van Gelder once said "I love re-mastering early recordings. Those engineers wore ties to work."

If the sound recording is lousy the performance better be amazing or the record/CD etc. will be relegated to the back of my mind.

An example of studio wizardry rescuing a lost cause is the 2011 release of Robert Johnson: The Centennial Recordings. Steve Lasker and Seth Winner accessed the finest available original and test pressings and, after using the most advanced transfer techniques to capture the source material, removed all the sonic noise (clicks, pops, stripped grooves, etc.) knowing some loss of high-range frequencies was inevitable, resurrecting the clarity of those 1930’s recordings to an astonishing degree. I can listen now without flinching.

my point is that poor recordings can, at great expense, be overcome if the performance warrants the effort.