I don't want to read the entire thread, it's so long, but I want to make a point that I hope has some value and hasn't been done to death already (apologies if so).
I don't understand the, to my mind false, binary split. Surely there is plenty of subjective information that has value, especially when gathered from many listeners in a controlled setting; even if the setting isn't a controlled one, it doesn't mean what a listener hears isn't related to actual playback, as a matter of course. A subjective opinion can be purely a figment on one's imagination and some people are more imaginative than others, but there are many occasions when humans have to trust their instincts before an abundance of data comes back to affirm something (or else there would be far fewer of us on this planet). We may not be as accurate as machines, but that doesn't mean we are wholly inaccurate.
If a subjective reviewer is tested and it is found their opinions seem to chime with the objective data, then surely their opinions have value, to some extent. The correlation would prove it isn't purely a feat of imagination on their part.
This is an argument, to paraphrase, one hears a lot :
"objective measurements are everything and if you, as an individual, are hearing something that doesn't chime wholly with the measurements, then you must be the one at fault"
Well, maybe that is the case. Almost certainly (as Amir said, further up this thread) if you are hearing differences in cables and such, when they are proven to be working within spec, it is a figment of your imagination.
However, if you are hearing differences between loudspeakers, and that difference is not obvious from the measurements typically taken, is the science of loudspeaker measurement so settled that it can be said, without question, that what you are hearing is just a phantom, a figment of your imagination? I don't believe so.
The science isn't settled. The way the measurements are taken is not settled. Which measurements are taken and how is not settled. It may be 70% or 80% of the way there, higher still perhaps, but it is not 100%; therefore it seems unlikely that the measurements alone (as it pertains to loudspeakers) would convey 100% of the listener experience and/or preference for any particular loudspeaker.
This would suggest, regarding loudspeakers at least, you cannot trust the data on its own, and that you do you own ears a disservice when you say they have no role to play in the process, let alone suggest that they exist only to trick you.
Look at the Harman curves. This is subjective data collected, en masse, for the purposes of understanding listener preferences. The preference curves seem to suggest that people prefer, by and large, one or more downward slopes at high frequencies. Well, this isn't accurate reproduction, is it? An accurate reproduction of the signal would be a completely flat FR in room, no? Yet, if the overwhelming majority of people will find such a scenario "too bright" for their tastes, then it is likely neither here nor there whether that would be the accurate thing to do regarding reproduction.
That there were strong correlations in how people preferred sound reproduction in the Harman tests, suggest that subjective preferential information is not anywhere near as scattershot and random as some suggest. You can't account for one individual very well, but when you have many people, then preferences often chime with each other to a greater extent than they don't.
The subjective way in which people appreciate sound has value. The value depends on the individual, of course, but manufacturers like Harman seem to be under no illusion that a deviation from accurate, isn't necessarily a deviation for the worse; if they thought that way, they wouldn't have bothered doing the studies in the first place and, if it was found that many/most peoples tastes deviate from accurate reproduction, they would have stuck the information in the trash and not published it.
Will people look back at our posts in 100 years (as we look back at the writings of those 100 years in the past) and giggle at how silly we were to believe x thing, when that thing was proven to not be the case, as far as they are concerned, long ago.
We are only following the science as we know it, but it is not settled, therefore the idea that the measurements taken, as they stand, represent wholly the experience a person might have listening to any given speaker, seems unlikely. To say that subjective impressions have no value whatsoever, or exist only to trick us, is also unlikely.
Any extreme position in either direction seems not to lead to a full, scientific understanding of the question.