I set up my room using acoustical principals but without using specialized products. I don't have any glazed pictures in the room. The art on my walls are wood carvings and tapestries. It's relatively balanced. I've done this so many timesI feel I'm getting a 6th sense about getting good sound out of a room. What I've noticed is that old homes with thicker, stiffer walls do much better than the thin drywall in newer homes. Older, concrete-based acoustic ceilings are gold.
Is it the best case scenario? No. But it works well enough to fool me. Now, I've had better rooms to deal with but I do also enjoy looking at the room I listen in as well. It's part of the equation for me.
Most treatment, to me, looks ill. And, let's be honest, the sound/signal does not care if it's a specialized product or not. I imagine even the best treated rooms using the latest tech aren't a perfect exploitation of their potential.