Yes I understand this argument and maybe I'm belabouring the point now, so I'll stop posting after this for a little while. But let's take karajan and berlin phil for example. Its generally thought that a lot of the deutsche grammophon recordings of his are really sub-standard compared to say, something that decca would produce. In some cases it really does sound like they just used one stereo mic above the orchestra and post-processed everything else. And many a time I am sitting there listening and just moaning at the poor recording instead of focusing on the music and wondering whether there's a piece of equipment out there or some process that can make it sound 'better'.
Doesn't this happen to anybody here? Or am I succumbing to the dreaded bias and wasting my time?
So if I'm understanding your example correctly, you desire to post-process the recording into something of a much higher fidelity than it currently is.
The pursuit of virtual speaker simulations in headphones (HRTF, Smyth Realiser, etc) can be considered as one parallel to your cited example.
Another, in the field of image processing, is the research into colorizing old, faded, black & white photographs in a manner that looks natural and of a fidelity that matches modern day equivalents. The most recent attempts have been done through the use of machine learning algorithms.
And yet another I remembered reading about, in video processing, was the work done by fans in restoring/upscaling old Star Trek episodes into something much higher res, and that actually looks like it was originally shot that way, again with machine learning algos and analysis.
So based on my understanding of what you're asking, I would say that while it's probably doable (post-process a recording into something 'better'), it's definitely not going to be a trivial undertaking that can be accomplished with a couple pieces of consumer electronic equipment.
Again, using your example, say a series of EQ filters are applied to make recording A sound 'much better' (to your ears). But these filters will probably screw up recording B and you'll need to do another set of filters just for B. And so on.
Oh. Another example is the autotune algorithm. Not the Cher effect, but how the producers use it in more subtle ways to correct vocals. In your case, you're talking about some magic auto tune algorithm that will analyse and 'fix' your recoding.