OP… “I am stuck in the sound quality deterioration spiral.”
This can happen. It is unlikely in your head. There are so many variables and emotions involved… and the decision making process can become super load the decisions you make. If you have calibrated your thinking to the wrong set of parameters… let me just make something up… you carefully read / reread marketing info, and make decisions on measured specs, and actually like warm natural sound and are increasingly investing more… you are likely to be repeatedly disappointed.
The real trick is to recognize that there is a problem with either your decision process or the variables your track, or sources of info… etc.. Each step should be a significant advance… every one, and proof of process.
So, the only rational thing to do is stop where you are and deeply examine your decision making process… where is the process not working.
I would start by listening to other systems… dealers, friends, Audiogoners… cheap, expensive… etc. you want to find some that you really like and hate. Look for venues to listen to live music. You know you are smart… you can figure this out. Then read pro reviews on these. This will be your pursuit for a long time. You want an epiphany. “Oh sh@t!, that is what I was missing.” Take all the “addictive dedication” and invest it in figuring out why the expected outcome of sound quality is not what you are expecting, and what is your desire.
In the first years of my pursuing the high end I made some mistakes and some great purchases… I had to spend a lot of time figuring out the difference. After that my purchases became very satisfying and generally exceeded my expectations.
Along the way I made up little rules, like always invest at least 2x or more, or it is likely to just be a sideways trade of one set of strengths and weaknesses for another.
