It’s a question of where it is done. Processing done to the core happens prior to network buffers which add a few seconds of delay. This is fine for volume leveling but not for volume control which must be responsive. Volume control happens right before we hand off the samples to the driver within the audio endpoint. This could be a roon ready device, roon bridge, a phone or tablet, etc.
Roon generally assumes that cores have a lot of processing power to do expensive stuff like DSD processing but we don’t make the same assumptions about audio endpoints as they are much more diverse and often resource constrained.
Like I said above the constraints are less harsh than when this was originally engineered so the door is at least a bit more open for this now.