In my room it is all about the cornersIt is always about the corners.....
It is a many bodied problem with multiple interactions, inputs, and outputs, which is why it can be so difficult to get a handle on it.
Audio gear is the same. The interactions inside the ’black box’ (the device in situ) are complex so the capacity for misunderstanding input as measured to output... are manifold - when it comes to attempts at rigor and simplification.