How close are we to the real thing?
Since I listen exclusively to classical, I find this subject fascinating.
The truth is: we are very far. Why? - Because audio and acoustics are still treated as an art, not a science. I think that audio is now in the same stages as medicine was in the Middle Ages: we know the basics (anatomy), but the remedies are still experimental. A trepanation is made to extract madness; blood letting is supposed to be the cure for many illnesses. Our amps, cables or speakers are tweaked in the same empirical way.
Sound engineers and other people along the music production line DO NOT scientifically aim at achieving an exact reproduction of the acoustic sound; instead, they mainly make sure that the recording sounds nice, and they all use different microphones, monitors, consoles, room sizes, etc.
On the listener's end, we all use different amps, speakers, and our rooms all have different acoustics.
If there was a real willingness to achieve the sound of the real thing, the whole process would have strict standards: microphones, amplifiers, consoles, cables, loudspeakers, rooms, etc. would have ideal specifications. Listeners who can afford would be able to reproduce these specifications at home - if necessary going as far as building a room to the exact specifications.
The Middle Ages ended 600 years ago. Let's hope we won't have to wait that long for audio to be close to the real thing. All what it takes, is one producer setting up a recording standard that can be replicated at home.