I think you make a good point about Elac and limited/differentiated capabilities, but I suspect that point has been absorbed within Roon and we won’t be seeing many similar arrangements. I have no special knowledge about that, it’s just a guess.
As a certified card carrying fanboy it’s pretty hard to be objective about RAAT. I think the thing that makes it a natural successor to existing protocols and inherently attractive to hardware manufacturers is that it gives control of timing to the clock in the end device. Will that be enough to make people move from Sonos to Roon ? Maybe. Sonos is a closed pond. RAAT hopes to be an ocean.