Sure, live music occurs in an acoustic space and that’s an important part of the original sound. But a good recording captures that sound and that’s what I want to hear. An untreated, live room distorts the sound in the recording by adding sound that wasn’t part of the original performance. No different than noise.
A room needs both diffusion and absorption for different reasons. But the net effect of good treatment is reducing the sound of the room and allowing you to hear the recording without added noise, which is what reflections are. Noise that wasn’t contained in the original recording.
You’ve made a great case for a pair of headphones or near-field listening.
Your argument doesn't seem to extend to studio recordings, does it? If I'm listening to Aja by Steely Dan, which is mixed to the nth degree, what kind of "room acoustics" are in there? Or EDM? It is up to my gear and my room to provide a canvas for that sound. The canvas can be good (well treated room) or bad.
For some reason, when I’ve treated my room and gotten the frequency curve and reflections where I want them, the music sound full, well placed in the sound stage, and relaxed. When I sit near-field or put on headphones, I feel suffocated.
No, there’s a difference between a good sounding, properly treated room that is not just about "adding noise." It is adding naturalness, the physiologically-based experience which was described before. If this was not true, most people on this forum would just be wearing headphones or would have formed a hobby around collectively bad taste.