Do hi-end DACs offer true value or diminishing return...

@mahgister , amen.

I jumped from a midrange DAC (about $2k)  to a much more expensive one.  But of course I didn’t trust myself so I asked two professional level musicians to be my judges.  Took about 12 seconds for both to describe 1/4 and 1/8 notes on a bassoon that I didn’t have a clue about.  My point being that bias is huge.  You really have to get a neutral involved to get rid of the bias.  

there is a correlation with the price... do you want to understand it? - a good analogy - drive a cheap Korean or American car ... and then try a BMW 750 Li or a Mercedes S class ...
of course, all components of the path are important - high-quality recording, a special room, good electricity, other devices and their synergy ...
Do you need it? - it will be expensive and long - but you will get an illusion that will bring joy ...

You can also get by with less money and get acceptable sound quality.

You can’t get by with small funds - this is a lie ... start from 10 K

Funny. When you call professionals, and ask about adding more DAC, changing a DAC, etc. … they’ll usually ask the question: “Well, can you REALLY tell the difference?”

And I’ll have to say, “No”

There are just too many variables which have even more opinions. There are no facts. Your ears and your room are the only facts… but they cannot be compared to another’s… same deal. 

My experience with DACs a is that a very well-designed unit can be had for under 2K and the real performance differences come from the choice of power conditioner, cables, isolation and system synergy. Are higher priced units potentially better? I would say that they represent greater potential, which may or may not be realized through the choice of the other components in the system.