mick wrote:

Could it be possible that non-linearity and the built-in distortion
factor is what causes the difference in sound? That a perfect "wire with
gain" amplification is actually *wrong* for our ears simply because it
does *not* introduce the distortion that our hearing associates with
"real" sound?

Interesting point but I think perhaps a non-starter.

If listening to a live performance, for the sake of argument, from a
point source instrument, our 'inherent distortion' is the only thing
impacting on the signal.

If we now make a recording of the signal, again, for the sake of
argument, with a perfect microphone, and played it back from a single
speaker in place of the musician, with a perfect speaker, we should
expect the speaker to produce the same waveform as the musical instrument.

if the same waveform is produced, the ear will apply the same distortion
as before, and the perceived sound should be the same.

If we can agree on the above, this suggests that in order to hear
something that is true to the original sound, we need to have distortion
free reproduction.

IOW, the ear introduces the same distortion all the time, so introducing
more distortion wont help.