Jack,
I disagree with the first paragraph in your opening question. Your objective will be different from mine and probably most other contributors on this forum. So, it is subjective.
I significantly agree with the comments in your third paragraph, especially the latter part.
It has taken me 40 years to get the sound that I am very satisfied with. No longer do I criticise my system because it always provides me with an entertaining experience and, that's all that matters.
I have learned how to audition new components, passively, to begin with. I also have studied the perception of hearing and, therefore, I observe not only the music reproduction, but my state of mind and wellbeing at the same time. High end hi-fi systems are very fickle and can require re-tuning from time to time. But so is our ability to LISTEN.
ATB,
BP