Sound quality differences in streamers

First of all, it’s dCS, not dSC, and to my knowledge, their least expensive model starts at around $22,000.

Personally, I don’t own (but have auditioned) any streamer over $1,000. That said, I believe you can clearly hear the difference between a Wiim and a truly high-end streamer—at least in terms of pricing. This belief comes from the ability to easily distinguish differences among sub-$1,000 streamer/DAC units out of my humble system. The real question is: where does the point of diminishing returns begin?

Price doesn’t play the music. For example, my $399 Cambridge Audio MXN100 sounds noticeably better than (1) the $330 Wiim Ultra (with Smsl ddc), (2) the $399 iFi ZS, and even significantly better than the $850 Eversolo A6. All were tested using their internal streaming sections, the same external DAC, and low-noise power supplies. The sonic differences are apparent and, in my opinion, may mostly come down to two specs, including (1) jitter noise and (2) electrical noise, that one needs to watch over in selecting the gear.

Finally, I encourage you to treat your room acoustics, optimize speaker placement, carefully select cables based on specifications (not ad-hoc recommendations), be mindful of system synergy, and train your ears to better reveal those differences.

Lumin U2 mini with the Sbooster power supply » Allo Shanti supply on the WiiM Mini

This equal tipping of the scale really surprises me—a lot—given Lumin's reputation and the significant price difference. I previously tried the WiiM Mini (without an LPS) and found its lightweight low-end notes unacceptable. Some people told me a clean power supply would make a significant improvement, but I didn’t pursue it due to the Mini’s limited connectivity options.  The Pro+ and Ultra, which I tried later, performed much better in that regard, so I’ve kept them since.

Later on, I came across at least two not-so-impressive tests of the Lumin U2 Mini. One of them is this.  I don’t wish to jump to any conclusions about the performance of this particular Lumin model, but I suppose there’s a valuable lesson to be learned.

A server for $29k.  Forgive me, but that’s just dumb.  Really dumb.  Like insanely dumb.

I'm not sure if the word 'dumb' is being used to describe the buying decision, the behavior, or the individual who made that decision. Here's how I see it: I'm frugal, and I tend to be cautious with my spending—even when I could afford something luxurious. But I've come to respect those who have the disposable income to buy truly luxurious things, even if those purchases sometimes irritate me or others, including people like you. They're not dumb. If they were, how could they have accumulated the wealth to afford things that we can't? 

I’m fully on board with your analysis from a purely specifications-based standpoint. But the subject touches on something deeply human when it comes to consumer behavior around luxury items. Let me try my best to summarize it:

1. Aesthetics - using your example.  I could imagine / visualize the Antipodes Oladra might look nicer, slickier

2. Perceived quality / Justification biases - better design component, craftmanship, durability / reliability

3. Emotional value - Luxury items make them feel 'exclusive' and exciting to own

4. Social proof, symbol of taste and wealth.

Look, as I mentioned before, money is something we’re not born with, and something we can’t take with us to the grave. If one has it, spend it as one pleases — if one feels like it or is willing to.  It’s not really our business, although I do sometimes sincerely urge them to share their wealth with those who need it.

Anyone who’s compared a $400 streamer to a $2k+ streamer will tell you there’s a very significant difference between the two.

That's a laughable fallacy—there are numerous counterexamples.  Here is one. 

@ricred1 You must be directing your comments to someone else.

Now you should rest assured that @mdalton was not directing anything at you.