Help settle a streaming argument!

It seems logical that the streamer (or CD transport) should not matter, but my experience has been (in both cases) that it does.

Streamers make a difference in SQ in my experience

Absolutely!   I went from a Vault 2i which was my first streamer and a great way to get into streaming and stored audio.  I replaced it with an Aurender N200 and the difference is not subtle.  It was a worthwhile purchase for sure. 

That’s a loaded question ,for the Quality of the streamer can make a big difference 

in its power supplies,and regulation , it’s quality of Crystal or Clock it’s processing 

this is even before you get to the dac , also the Quality of the Ethernet cables ,and USB cables, as well as power cord quality.

every factor here counts in a quality Audiophile streaming system.

99% of these respondents probably use usb to the dac, and if this is the case, the best sound you will get is mediocre at best. 
Change your test: get a dac that uses Ethernet (which is far superior than usb) and test different servers. Your results will be much different. I used to use 1 of the better steamers mentioned above with usb and then when I switched the dac to use Ethernet and/or i2s, I sold my streamer.
1 more test: use i2s going to the dac (i2s is also superior to usb) and test different servers. Again, your results will be very different.