What makes a DAC so expensive?

I just bought the RME adi-2 FS DAC and it is awesome.   For me it checked all the boxes, great sound.... unbelievable feature set,  made in Germany,  full function remote, and most importantly at the price where I felt it made sense because let's face it, digital technology moves fast.  It easily bests my NAD M51 which is no slouch and was twice as much 7 years ago.   So for me this was the best bang for the buck.    

the dcs stack is incredibly good

I'm learning a great deal here. I also find some of the stated/implied money-values interesting and thought provocative. 

These phrases, particularly: 

Those that don’t want to spend the money justify having not done so. 

Those that have spent the money justify having done so. 

@jl35 I'm actually not able to purchase the cited DCS stack - looks like it's $80K - unless I sold everything, but the house. Is it worth it? Why? Why not?

And by the way, I'm totally open to discussing the worth of wealth, it's associated values, and the way people treat each other as though a few hundred-thousand (or millions...) dollars worth of money in the bank is somehow one of the most important features of one's character, or actual value. We do live in a world where plenty of people rank the value of others based entirely on their perceived income station, and this happens from all positions on the scale of perceived wealth.

Nevertheless, having HUGE money is not inherently bad, and we can perhaps benefit from some of the things made for big bucks $$$!

For instance, I'm very interested in what would happen if one of the people owning a $50K+ system placed a $100 DAC into that system. The Modi 3, for $100 sounds damn good in much of my listening, so I'd love to see what happens when we punch through the biases we can punch through, because I am of the opinion that people with $100's of extra K's have to make that money mean something, so money has a way of magnifying biases, potentially, or am I missing something???

IMO, you just can't make your millions mean much if you never use them, never 'manipulate them, and so we see the birth and rebirth of luxury, to make all the stowed money mean something.

What I want to know is how these things DACs truly compare, with awareness of the need so many people have to make their HUGE money meaningful... 

This is to say, can you set your biases aside long enough to take a low cost DAC seriously, if your gaze tends to rest on DACs that cost $4000, $8000, $40,000?

I am sure that people with abundant cash have been able to explore more of the high end stuff, but do they keep the low end stuff available, as a valued part of the equation? What can we learn from such people and are they willing to come forward, to disclose some of the findings I've indicated...?

Measurements on the new Schiit Modius, which costs $199, are compelling, but more importantly, for this low-coster, those reviewing the Modius claim it's better than the Modi 3 and one person, quite interestingly, claimed it was better than his RME adi-2. Let me be clear, it was not a side-by-side comparison, but claims were made based on previous experience with the DAC. 

So, I'm still pondering this issues of OP amp and power supply. How do these show up in the measurements?

Is compression reflected in THD+N. I'm attempting to discern how useful the available measurements have become... I hear critique or power supply and OP amp in these low cost DACs, and I want to know if there is any other way to discern the impact of these pieces before plugging it into my system?

Heard a little commentary and I did enjoy the pictured argument between a dead man and his measurements. It's an apt metaphor. I thought it could be refined by taking measurements of a piece of meat one might buy from the butcher. It might come in at just the right weight, to meet one's needs, might even be the right temperature, might even be the right cut, etc.... none of this is proof of flavor!

Finally, the Modius, low cost beauty? 

Does this statistical test (below) reveal anything useful about the power supply, OP amps, or ANYTHING else?

Please offer a carefully reasoned assessment.

https://www.audiosciencereview.com/forum/index.php?threads/schiit-modius-balanced-dac-review.13769/

I cannot consider the DCS either, was just lucky to get a long listen to it...

Does this statistical test (below) reveal anything useful about the power supply, OP amps, or ANYTHING else?

I assume you looked at the measurements. Is there something you didn’t understand because they reveal everything useful. Basically all these tests are doing is showing does the power supply leak audible noise into the signal path. Does the reconstruction filters get rid of high frequency distortion? You take those top 20 DACs from the $199 Modius to the $ 11,000 Mola Mola and noone except perhaps a few young people with extraordinary hearing could tell one from the other. It’s only in audiophile forums and high fi sales floors anyone thinks DACs are a problem anymore if they are well engineered as these are. Engineers are just chasing specs and trying new things DACs are no longer a mystery they haven’t been for years.