"Realism" is unattainable. The recording microphone is in no way as sophisticated as the human ear; something is always lost when a microphone picks up sound. And since our rigs are at the mercy of the source media, the best we can hope for is the most minimal of sound degradation through OUR audio chain. Even if you had the "theoretically realistic" system, you are still going to be subjected to the recording anamolies that will tell you it's a reproduction and not the real thing.
So it now boils down to what our individual tastes prefer - because no two people will hear the same thing. We all have an inherently personal response to live sound: different experiences, physiology and tastes. So if there was no equipment coloration, we would then respond to the recording losses and may or may not like what we hear. That's what neutrality will do.
But if we like what we hear, and even if it's attributed to even-order harmonic distortion, cross-over distortion, cable losses, whatever, then we spends our money and makes our choices. We will never attain the realism we hope for - but oh the fun in trying.
So it now boils down to what our individual tastes prefer - because no two people will hear the same thing. We all have an inherently personal response to live sound: different experiences, physiology and tastes. So if there was no equipment coloration, we would then respond to the recording losses and may or may not like what we hear. That's what neutrality will do.
But if we like what we hear, and even if it's attributed to even-order harmonic distortion, cross-over distortion, cable losses, whatever, then we spends our money and makes our choices. We will never attain the realism we hope for - but oh the fun in trying.