You are right once it reach certain level, it is hard to improve
Actually I couldn’t disagree more. With very resolving systems any change in the system is obvious. Fine tuning small details becomes paramount.
As as a case in point in my system over the past two days I’ve spent many hours firstly getting to appreciate an update on my CD mat (Marigo Clear Transformation to new Aida) and then going back and forth on the impact of introducing a Furutech damping stand under the power cord to the power conditioner that drives my mono blocks. Both of these changes had profound impacts, one I ultimately decided as positive (the mat) and the other negative.
But in both cases the differences were very clear and audible. High resolution means needing to sweat the details I’m afraid and the benefits when you get it right keep adding up