Is Recording quality the real culprit?

Regarding rock v jazz historical recording quality, a key difference is that rock music is played on amplified instruments and is in general played a lot louder. This creates major issues with spill and achieving adequate levels of separation. In addition, you often have more instruments - or more instrumental tracks where overdubbing is involved - and more instruments sharing the same frequency range. All of this requires more outboard equipment and more complex mixing desks, so in terms of purity, the signal path is more compromised. And despite the fact that classic outboard gear from the fifties and sixties is now lusted after, a lot of it doesn't sound that great if you apply hi fi technical standards to it. Lastly, when multitrack recording was limited to four or eight tracks it necessitated signficant amounts of bouncing to get the desired track count, and bouncing seriously compromises fidelity. So it's not that surprising that historic jazz on average sounds a lot better than historic rock.

A BAD recording played on a good system still sound bad.

A poorly recorded great album still sounds like a great album when played on a good system.

@yoyoyaya 

Amazing reply. How do you come by such great insights into all this? Other comments you make are also impressive.  Even the one thread you created about heavier vinyl is also very interesting.

@emerging soul - thank you. I think that playing and recording music helps a lot to understand how music is reproduced. I've spent a long time listening to, playing and recording music. The recording and reproducing camps are often divided and I try to bridge the gap between the two.