Are "streamers" the new "transports"?

Absolutely yes, with the same issues regarding the digital output plus the usability due to the app for the control of the player. Bluesound app is very good, Aurender app is good too but both are somewhat limited (not so for most of the users but I am quite nitpicky on this regard). 

My system is streaming based, I have an Aurender N10 streamer connected via AES to my DAC. Using a dedicated streamer absolutely a huge improvement in SQ and indeed its highly recommend if you wish to depend on qobuz and tidal.
What i have recently discovered and its quite shocking, but hearing is believing, and some of these tweaks are cheap to test, is the quality of your ethernet makes a substantial difference. 

First of all, forget Wifi. Your streamer must be hard wired using ethernet. That's why some streamer don't even have Wifi option.
Start with your typical three in one commercial "router" like Asus, netgear, tp link etc. These are a router + a switch + wifi hub all in one. Get a cheap router only, from a company like Ubiquity, like edgerouter x. we are talking a 150 USD investment here only. Create your internet connection within the new router, connect your streamer directly to it. Then you can use your old router as a wifi hub only (for your regular usage and also for your controlling device to see your streamer on the network).
If the improvement in sound of eliminating wifi circuitry interference from your main router doesn't shock you, i don't know what will!!
If that cheap step proves to you SQ improvement is possible through 'cleaning' your ethernet, you can try other steps such as adding a level of optical ethernet converters for further isolation (also relatively cheap). Then for a final icing on the cake, you can get a fancy ethernet switch from likes of Sotm or uptone. This is an expensive step, but after trying the earlier cheap ones, you might want to stretch to this. Naturally, high quality shielded ethernet cables like AQ vodka or Sotm make a difference as well. 
I believe we are still scratching the surface when it comes to digital music playback. But its fascinating how such services like qobuz and tidal could sound almost as awesome as a CD transport if used with a proper chain of playback. Starting from your router.

Outside if the "cost no object" gear ($5K+), is there a difference in the transmission of the digital signal that then creates SQ improvements via the SAME DAC?

Yes, and I think sonicjoy’s post is spot on. FWIW, Chris Connaker (Audiophile Style) just announced their Product of the Decade picks and in the hardware category he chose the Sonore Rendu series.

https://audiophilestyle.com/ca/bits-and-bytes/audiophile-style-products-of-the-decade-r865/

It's been half a decade since I had a disc-spinner in my system, and I've never looked back.

OP here...;-)

Why should I "forget wifi"? I dont get it. 
First, I cant, as my stereo is across the room with no ethernet jacks around.

I have found musical satisfaction by streaming Qobuz via Bluesound to my Chord Qutest.
Also "stream" my library of music on my MacBook Pro via AirPlay to the Bluesound to Chord.

Ive been at this hobby for 30 years.
My current set up is working for me. I can A/B the same song on my CDP/Chord and Bluesound/Chord and I cant tell the difference. I'm an amatuer musician and also have a decent rig: Belles amp to Dynaudio Speical 40s with all DH Labs cables.

This thread has confirmed to me that, yes, there are more expensive solutions out there yet not many can even articulate in 2 sentaces WHY they would be superior to Bluesound assuming both solutions use the same DAC.

Stepping off the merry go round...