Yes, but this inability to isolate particular aspects is just as true of analogue recording systems. For sure, trying to compare a recording with the original is difficult because of the difficulty of finding an objective method - you must make assumptions about which aspects of the sound you consider make it closer or further from the original and independent ways of measuring those.
That's right - and as music is listened to by people (whether live or recorded) using their ears and brains as the 'measuring' instruments then the assessment of the accuracy of the recording has to involve listening tests as even the most sophisticated analytical systems simple aren't able to uncover the subtleties and key components of sound that are absolutely obvious to us. So they might be great at measuring frequency response or dynamic range, etc but that tells us very, very little about how a recording (and it's playback characteristics are).
And frankly most audio equipment is subject to the most crude of analytical measurement testing. So it is often almost impossible to tell the difference between cd players from standard testing approaches used even by reviewers, yet the cd players can sound dramatically different. Why, because the things that are critical to how something sounds to the human ear are the most subtle, because the human ear is far, far more sophisticated at listening to real sounds than measuring devices.
So I mentioned the inability of even the best 'machine listening systems' (such as the ones being developed and used by my academic colleagues who are UK and world leaders in this area) even to be able to determine how many instruments are being played, let alone which or whether their reproduction is high quality compared to the real sound. There was also some rather fun research in which the 'machine listening' algorithms were challenged to tell between different genres of music with incredibly distinct musical style (e.g. classical, reggae, rap, country, metal etc). So the system was 'taught' using example pieces typical of the genre and then was presented with 'test' pieces, similarly typical of the genre - its ability to differentiate was really awful. Most average listeners would instantly get it right - yup reggae, definitely rap - the machine can't do it.
I suspect, that as long as an analogue recording contains enough detail (a digital recording will carry more information)
Wrong, wrong, wrong.
For crying out load the whole point about digital is it converts a smooth analogue signal into a bumpy, lossy digital one. Draw a perfectly smooth sine wave, convert it to digital and it becomes a series of bumps. Sure as your resolution increases it better approximates the original analogue signal, but never attains it. Digital inherently contains less information than analogue, and in practice (see above) a vinyl record spinning at 33rpm can produce data per second rates at least 4 times greater than cd, even for the inner grooves.
warmth and colour added by the equipment just makes it sound better - as long as it still good enough (eg. by preventing vibration feedback to the record deck) not to lose any more information. Quite often a CD played back through valve power amplifiers can sound better than through a conventional amp - here any information possibly recorded by an analogue tape but not by a digital recorder will have been eliminated.
Indeed smooth amplification systems can hide the limitations of cd and make it pleasant sounding, but those limitations still exist, they are just hidden.
There are of course limitations of vinyl systems, not least the greater challenge to be able to extract the information (indeed the greater amount of information) from a vinyl groove than you'd get from a cd. But get it right and the ultimate ability to reproduce sound in a realistic and believable manner is simply greater for vinyl for a whole range of reasons, not least that it is analogue and not inherently 'lossy'. And most experts agree - surely they can't all be wrong.
Now don't get me wrong here I'm not talking about nostalgia vinyl fans. There are 2 main groups of people who love vinyl. The first (the nostalgia type) love the tactile nature, they love the crackles, they love a warm, smooth, punchy sound (which is often a product of rather poor vinyl playback). That kind of pleasing sound that is like wrapping yourself in a warm blanket, which CD struggles to achieve. But that's not anything to do with accuracy - the second group love vinyl because it is more accurate. A great vinyl system isn't warm, smooth, muddy (and lovely in a euphonic kind of way) it sounds like a group of real instruments playing together - in fact it is often quite the reverse of the classic warm vinyl sound - it is lightning fast, pin-point accurate, absolutely precise - some might think cd like, but actually startlingly real. But where it is better is that it is never harsh (albeit lightning fast), it separates players in 3D (something I've never heard CD do effectively, so not only can you tell that the drummer has a cymbal higher and to the right of another cymbal, but that it is positioned behind (or in front of the other one).
All I can say is find somewhere to hear a really top notch vinyl system and you will be astonished - it won't sound like your vinyl comfort blanket, but like the best cd you've never been able to hear - why because standard cds simply aren't able to attain that fidelity of reproduction.