I think as room size varies, so do the possibilities of equipment variation while achieving "full" optimization in the room. The possibilities are potentially endless and we then can argue the merits of particular boxes, wires and source type and material. There are people that doing this for a living.
You are perfectly right for sure...
But you forgot that acoustic and psycho-acoustics laws or principles and methods apply to any room and any system, these laws and methods are one of the main sources of optimization for a system/room/ears...
Never mind the chosen system, sometimes a low cost system can beat a costlier better one because the better electronical design is badly embed, or uncontrolled in the mechanical,electrical and acoustical working dimensions...
We could learn many things rotating our gear, but at the end the essential is how we must learn to control the final chosen gear especially in the acoustical dimensions...
My best to you....