Those who dogmatically adhere to this as the only valid methodology for equipment/system evaluation seemingly ignore the fact that all live, unamplified music is not born equal.
How about a non-dogmatic approach? For instance, I look to certain characteristics I hear in "real life sound" and seek some of those in reproduced sound. That is, the aspects that I find can actually be reproduced to a degree I find pleasing. Works for me.
Take the acoustic guitar, for example. What kind of strings are being played? What techniques are being used? What is the shape of the guitar? What is the size of the guitar? With what wood is the guitar made? Are there inlays in the neck? Paco De Lucía (who I saw when he played that infamous show with Al D and John M) will sound very different, at least to those in the know, depending upon the answers to these kinds of questions.
I'm pretty sure The Absolute Sound crowd (e.g. Harry Pearson) was aware of that. What they tended to do was try to identify certain aspects of "real acoustic sounds - voices instruments, symphonic etc - in real space" and look for those aspects in sound reproduction. They were continually aware, from what I read, of the gulf between real and reproduced, so they were cheering on gear that got "closer" rather than "further away" from the real thing. Sort of like hoping for a general "gestalt" of live music, in that sense.
So it's not like you have to always know precisely what any particular acoustic guitar sounds like to have a general idea of how acoustic guitars tend to sound in real life, vs tend to sound on hi-fi systems.
As someone who has a habit of listening for those differences when I hear live sound, I'm sympathetic with that view. There seem to be aspects I hear with live sound sources that are pretty reliably different from what I normally hear through sound systems.
Of course, anyone is free to use whatever methodology floats their boat. But this purported evaluation standard does not withstand scrutiny and IMO it is no more valid than live, amplified music.
It's certainly an interesting question: can amplified music - Rock, Blues, Pop, Prog
- be used as a sonic touchstone as well?
In principle I don't see why not. I mean, in principle if you see a band in a club, you could replicate that PA system and playing their music through it, get a closer approximation of their live sound than you are likely to get through some KEF LS50s.
On the other hand, there's a certain level of power and scale to concert and even club PA systems that few if any domestic gear could approach.
So I don't know.
Personally I'm not trying to replicate PA sound systems. I played through enough of them to render my hearing fragile as it is.
That said, I've occasionally got a slight "reminiscent of concert sound" vibe when listening on my 2 channel system. For instance Rush's All The World's a Stage - the entire wall behind my speakers can seem to melt away, leaving a vast soundstage like I'm peering through the concert hall, and the sound of the instruments has that PA tone. Of course it doesn't come anywhere near the acoustic presence of Rush live. But there's something reminiscent about it enough to sort of sink in to the illusion. And that's really what I want most of the time - an illusion, with aspects of the real thing, but not all. Like watching war movie like Saving Private Ryan. There are all sorts of aspects that can "feel real" about watching it on my projector with surround sound.
But I sure as hell don't REALLY want guns and explosions and tanks to be as loud as they actually are! I'd be deaf after one war movie!