Thank you, @kevn
You make some excellent points. I am talking about two quite separate things.
Firstly, there’s improvements in sound quality from making some change to the system. Here I don’t think there is such a thing as diminishing returns. There is always scope to get closer to the sound of real live music. Some changes are transformational, but others are merely incremental.
Secondly, there is what I enjoy most about music. That is the place where the music takes me. A kind of altered state that allows me to get into it completely. I don’t doubt that good sound quality helps me get there, but so did marijuana when I was a student back in the day. However once I’ve arrived, do I really care that much about ultimate sound quality? Would it really matter if I hadn’t upgraded that last component?
In that sense, I may have found my enough as you suggest. In the past, much of my upgrading has been directed at solving specific issues. For example, overcoming the harshness of digital, taming of room bass resonances or balancing out an uneven soundstage. Perhaps, I have no dragons left to slay.
I am not saying that I can’t enjoy hearing the Yes Album as I’ve never heard it before. Yet it doesn’t excite me as it did on a car cassette player back in the seventies. What really excites me now is new music that I’ve never heard before. Perhaps all I need is a level of sound quality that gives access to it. In that respect, absolute sound quality may not be critical. On the other hand, maybe in time I’ll get used to the level I’m at now and again crave something better.
Sorry, I’m making this all about me. Others may well see things differently. It is a subjective experience.