There might be some exceptional older Jazz recordings...Yes there are and they equal or exceed anything produced today. "Jazz Party In Stereo", "Kind Of Blue", "Clap Hands, Here Comes Charlie", "Blues And the Abstract Truth", etc.
Viridian, I don't understand you analogy. May I suggest viewing the Mona Lisa under 20x magnification. You may lose the total artistic perspective, but your appreciation of Michelangelo's technique increases by an order of magnitude.
There are three points in my original post. First, the consensus is that equipment has gotten better. I don't disagree. Second, many of the reference recordings used to judge the improvement in equipment are 50 years old. I find that ironic. Finally, the recording equipment used to make the reference recordings was retired as obsolete by 1970. Commercial considerations forced this change. The newer equipment was better suited for multitrack/overdub recordings. That's not ironic, but sad. Although it's interesting to note that some vintage recording equipment (50 year old stuff) is highly prized by recording engineers. In fact, a whole industry has emerged of modern products, mainly tube designs, but some solid state, that use old circuit designs to recreate the vintage sound mojo. Now that's ironic.