Not sure what to think

I will not take away from any of the above responses but simply add a few things. 

You are at the mercy of the Microphone that picked up the sound from the instrument and or Vocal, along with the Recording Consoles Electronics also included in the chain is the 24 Track Tape Machine (If not done digitally) then the playback monitors and finally the Half track mastering tape which is used to create the Mother Stamper that presses the Vinal Record.

Also take into account the Engineer and or Artist that did the final mixdown. What were his or her ears (The Brain Does The Hearing) hearing when they mixed it.

What were the Studio Acoustics and Control Room Acoustics Like?

What kind of Monitors were they listening thru?

It goes on from there. There are so many variable's involved in the making the final product. This would also to some degree apply to a "CD". So I would say.. Enjoy what you have and crank it up. No two records or CD's will sound the same. Just tweetle the knobs until it sounds the best it can.

Having good equipment and the room set up and speaker placement goes a long way to enjoying your equipment. ENJOY!!

Could you explain the physics behind that contention? If all other parameters are the same, simply swapping any one component will absolutely make an audible change if there was one to be made.

The...physics. Well, we're talking about perception here, not physics. 

One can only hear a difference if other background factors are not obscuring or interfering. I can’t make it clearer than that. (Look at the ketchup analogy, again?)

@musicfan2349     A vast majority of Audiophiles understand the importance of acoustic treatment. Getting 95% + out of any level system is very difficult and time consuming where a professional might be needed to obtain that level. Many Audiophiles with modest or even upper level systems are not going pay for a professional room treatment set up. Take a look at the virtual system page with all the goofy large screens and poorly placed speakers and subwoofers(due to space or knowledge limitations). Ultimately acoustic room treatment can only be maximized when an entire system is completed thus being the last stage of system set up where the OP might not be at. Finally the room acoustic treatment issue is not a substitute for high level resolving electronics or loudspeakers BOTH are need for a true HEA system.

@hilde45 ...It still escapes me that room acoustics v. speaker type and its’ accoutrema gets bypassed by the ’well, maybe something else "upstream" will cure whatever seems....wrong....’
I know this after many spaces occupied got overtaken by ’audio-woke-ness’... Finally.
Ever since beginning to ’tweak’ that ’Room +/- Spkr(s)’ frustration formula with DRC have I been able to ’tune into’ whatever forsaken place and not let it sound like hammered s**t.

(Multiple speakers? Averages with a ’mini-tweak’... ;)....)

...and that's my 'excuse me'....*G*

@asvjerry I think I followed your train of thought.

My explanation is that many who love this hobby just can't do much to the space their gear is in -- but they still want to tinker, opine, etc. It's a natural and laudable enthusiasm even if, from a scientific standpoint, they're really just wandering around in the dark, muttering magic words to others in the same situation. And, of course, in a problematic room, one can change things by changing gear, but maybe not as much as wishful thinking would like. I would never spend a lot of money on gear in a bad room. Waste of resources. Again, not to take any joy away from those folks, everyone is the conductor of their own orchestra.

Some acoustic spaces can be dealt with using digital correction, but there are limits.