Once you start altering the steady-state room curve of a neutral loudspeaker, you are altering the direct (anechoic) sound, which, in case of a neutral loudspeaker, is direct contradiction with the results of the studies.
Neutrality has a clear mathematical definition. A neutral speaker thus would transfer the input signal 1:1.
An according pulse response would be a Dirac pulse. Such a speaker would behave correctly under steady-state aspects of course.
As music is not steady-state such a speaker also would behave correctly with transient-state aspects. But not only the frequency response would be perfectly flat, also the time behaviour would be perfect.
As the air pressure does not follow precisely the speaker driver movement at least for lowest frequencies down to the DC range I would even concede that a speaker described by a minimumphase highpass (corner frequency e.g. around 20 Hz) but otherwise flat frequency response could be described as neutral.
But I have never ever come across a speaker with such a neutrality. All measurements I have seen up to now show deviations from neutrality.
So how much deviation is allowed? When is a speaker neutral, when is it no longer neutral?
Is it neutral with a perfect frequency response but bad time behaviour? Can a speaker sound good when the frequency response is not flat?
Is there a common sense about a certain limit a speaker has to pass to call it neutral? When "neutral" speakers sound different which one is more neutral from a scientific point of view?
Is the resulting sound correct when the so-called neutral speaker is driven by an amplifier, preamplifier, DAC (which type? which brickwall filter?) or other sound source which is deviating from neutrality by themselves?
So what's wrong with trying to get the resulting soundwave closer to the original sound signal by correction? Why do people always stare at frequency responses and thus at the steady-state behaviour when clearly music is not steady-state? What's wrong with excessphase correction to improve a speaker under time-aspects?
I truly wonder how people talk about neutral speakers.