Hello, this is an interesting discussion that is relevant to solid state designs too, of course. Speaking of that, and bringing this discussion down to the level of physics and transmission of sound waves through air, what about this assertion from Nelson Pass:
https://www.passlabs.com/technical_article/single-ended-class-a/
Virtually all the amplifiers on the market are based on a push-pull symmetry model. The push-pull symmetry topology has no particular basis in nature. Is it valid to use air’s characteristic as a model for designing an amplifier? If you accept that all processing leaves its signature on the music, the answer is yes.