why expensive streamers

I’m not sure the price matters so much as a separate steamer matters and seperates tend to be higher end than integrated.  But as to why a separate streamer:

1.  Tech constantly changes. So it’s a generally better long term proposition to get distinct components, so you can just replace the parts that get outdated.  Or break.

2.  As far as why a nice streamer sounds better than an integrated:  

a  isolation from the noise on the network

b  isolation from the noise of the streamer itself

c.  It’s a dedicated component that does one thing well, with less compromise than in an integrated component 

d.  A quality streamer will:  check data, isolate and organize, and present the data in the best, most digestible, form for the DAC, allowing the DAC to do what it is supposed to do without it having to use resources making corrections or removing junk.

FWIW I use a Lumin U1X, which is not a cheapo streamer but hardly a $20k.  You can buy them used for $3-5k all day long.  I think they are about $10k new.

@mikhailark I have ripped my CD collection to uncompressed FLAC using dB Poweramp. I have it on an external drive hooked to my ASUS PC - the same one I use for streaming. I have listened dozens of times with different songs to see if I can hear a difference between the CD played through a Jay's Audio CD3 MK III vs. a Qobuz stream of the same file vs. my ripped FLAC. The process I use is to make sure the volume is equalized between sources and then play an entire song from the two sources I'm comparing at the time. I even take notes of things I've noticed and their place in the track so that I can listen for that event in the other source. FWIW I'm running through a Berkeley Audio Alpha Reference II MQA DAC. The streamed files are run through an Alpha USB before the DAC.

So far, the sound of the CD, the streamed file, and the FLAC have sounded identical. One of my main points is that people are spending thousands of dollars on fancy streamers because a PC supposedly adds noise and distortion to the signal. I admit I haven't compared  a 5 figure streamer to my PC but if my PC sounds as good as a CD played through a state-of-the-art transport then I think that's probably about as good as it gets. I don't think I've ever read a review that says that a high end streamer sounds way better than a CD or a ripped FLAC.

If your point is that we should be using a ripped FLAC as the control for comparison (I suggest using zero compression) than that is fine. My point is that comparing streamers to one another by disconnecting one and hooking up another without any means to compare them against a control is inviting expectation bias to influence what we hear. Without any means of comparison to a standard, I submit that the more expensive streamer will always sound better - along with the ultra expensive internet switch and the thousand dollar USB cable.

@cleeds   every time I go to a nearby dealer, they point to the "No Loitering" sign and lock the door.

grislybutter

... every time I go to a nearby dealer, they point to the "No Loitering" sign and lock the door ...

You must have treated him very badly. I can only hope you learned from the experience.

If we focus purely on the 1's and 0's arriving at the DAC in the correct, unmolested sequence then we can relax as all streamers will sound the same; all we then need to do is pick the streamer with an app/user interface which we like most.

Unfortunately, streamers also incorporate clocks so the sound quality they help produce may be affected by there being more or less jitter.

Unfortunately, streamers vary in the amount of noise they generate or pick up and this noise reaching the analog(ue) parts of the DAC will also affect sound quality.

If noise wasn't a thing and jitter wasn't a thing, all streamers would sound the same.  Unless I've missed something, and I'm sure someone will be along shortly to politely enlighten me if so...