Check in: How quickly are streamers and servers evolving?

I think the OP is answered. Here's where this thread seems to dead-end for me.

Thanks to @jjss49 @corente @headphonedreams for offering detailed answers with justifications about where things stand. Plus, your sense of what that implies for the best ratio of effort/reward ratio at the moment.

From what I see here, no one has offered a good reason to think that the streamer/server side of things is as stable as the DAC side. Many have argued well that this side of things is still changing rapidly (tied, as it is to the technological churn of the computer industry) and "investments" is a word deserving of quotation marks.

These edited comments from above will stick with me:

@jjss49

- dac technology is quite stable/mature...very good sounding dacs are less expensive than ever, from chi-fi and other makers -- this brings very good sound to the budget audiophile, and puts alot of pressure on makers of 3-4-5-6 grand dacs on really delivering something superior... they are really making super high quality output stages as in megabuck line stages with excellent circuitry, isolation, parts quality, often with tube buffering to get purity and beauty in tone to go along with the excellent resolution that can be gotten out of the d/a conversion stage...

- streamers are also fairly stable as pieces of equipment, but the key here is that streaming services are still shaking out, and this will continue for the next 5-10 years...each offering new interfaces, sampling rates, higher resolutions, specialized content, each trying to lock each other out from the user’s eyeball range with proprietary u-i’s, dedicated software wrap-arounds (witness tidal connect, spotify connect, and so on) -- this tough and evolving competition creates some level of instability (and risk) in streamer purchases, as these are basically dedicated computers that will need updating when the streamed sources change the game, their interfaces etc -- to me, the resulting indicated action is to buy a good low to mid priced streamer (that sound excellent, btw, so long as proper internet connectivity is provided) so as to keep options open and don’t end up owning an expensive brick down the road that are no longer supported/updated

@corente

DAC's: ...have reached the technological maturity...there will not be major changes in the next years, except perhaps the DSD ratio.
SERVERS AND STREAMERS:...just the opposite: you find many different technical solutions rapidly evolving and many commercial solutions trying to cover "everything": you go from "dedicated computers" for storage and streaming to totally separated solutions: server + streamer + renderer
indeed more, you have to consider your "music manager software" going from proprietary and closed hardware integrated solutions (Aurender) to proprietary solutions accepting external ones (dCS with Mosaiq, accepting Roon) to full open hardware accepting "music managers" using UPnP or Roon that is based in a network proprietary standard (RAAT)....comparing what I presently use (Mac mini dedicated and configured only for music) with a basic Innuos...I can clearly hear differences but they are not significant ...with the DAC...the differences were huuuuuge.
My opinion is to wait and see (two or three years minimum) and use a commercial computer or some specific but CHEAP one (Intel NUC, Green .....) or the very basic line of the dedicated hardware solutions if and only if they work with non proprietary software (Antipodes, Innuos, 432Evo, ............) and when market and solutions consolidate and start to be "similar" to spend the big buck.

Completely missing the point. But whatever. There's a lot to be said for, "Get off my lawn."  https://www.youtube.com/watch?v=NelBNtNm8l0.

   Most appropriate funny reply in a dogs life. Not exactly PC.   Right on Clint.

@rhodes My favorite Clint scene is when he yells at an empty chair.

We often talk about "as good as we will ever need". 24/192 really is as good as we will never need. Arguments can always be made that properly implemented 16/44.1 is already as good we will need (given that people can't reliably tell the difference), but 24/192 is so far beyond that, and so far beyond our hearing range, that yes, 24/192 as a data format, for stereo at least, is really as good as you will ever need.

Pick a lowish cost PC or MAC, somewhat modern, and it is going to run whatever version of server software you are ever likely to need for many years.

Pick a good DAC with a USB input, and you are now immune to data transmitted jitter, and contrary to popular opinion of those who have never designed electronics of any sophistication, creating a local clock for audio D/A conversion, of low enough jitter to be well below other noise sources, is not terribly difficult, and you certainly don't need an uber expensive 10MHz external clock, that is not an even multiple of the data conversion process and introduces jitter from cable transmission and edge detection.  If you want to read an article that shows total ignorance of digital audio, clocks in digital audio, and follows with an obvious stretch to say something positive, though quite clearly, there probably was no difference, read this drivel:   https://audiobacon.net/2018/09/26/sotm-sclk-ocx10-a-high-purity-10-mhz-master-clock-generator/2/

So what is left w.r.t. good sound?  Electrical noise on the USB I/F.  Invest in a good USB 2.0 High Speed Isolator (that does 480mbps), and a low noise power supply for the DAC side. Problem solved.

Assuming you have a good DAC, with a small outlay of money you now have something that has the ability to deliver audio quality that will match any server/streamer, and will keep doing so for many years. The only downside is the physical I/F, i.e. the computer, can be a pain to remote.