@kevn
Thanks for your friendly post.
A meal has ingredients, such as beef, which comes from a cow. The cow is processed and the material is configured in various ways that leads to the experienced taste perceptions.
A reproduced song has ingredients, such as sound, which comes from a plucked guitar (say). The sound is processed and the material is configured in various ways that leads to the experienced audible perceptions.
Everything at every step of the way is real. But all that means that everything at every step of the way exists. That’s a truism which we barely need to add.
The idea that there is some single "reality" or "original" which everything goes back to is, I think, the fiction. There is an event, an existence, at the start of the chain of causes. But it doesn’t have a meaning until someone interprets it -- selects certain details and omits others, emphasizes certain qualities over others and then takes all of those intial emphases and combines them (fries the beef, equalizes the audio, etc.). In other words, there is no "source" in a meaningful sense; there is a cause but not a reason which we could all agree on.
How close is the beef in the meal to the original? Or the audio sound to the plucked guitar? Depends who you ask, because people differ on which criteria are most important.
So, when you say, "While we may each taste real beef differently, we all recognise the taste of real beef as real beef, regardless of how it’s prepared" -- all I can say is the word "real" is not doing any work here. In the same way people will disagree about whether something said was a "witty remark" or a "subtle put down," people will disagree about what beef "really" tastes like or what a plucked guitar really sounds like. We can each "point to the source," as you say, but that doesn’t solve anything. There is nothing automatically meaningful to converge on.
This is how I see it. I agree that accuracy in music reproduction exists, but it exists in the same way that "pawns can move one or two squares on the first move" exists. In other words, accuracy is a word we use in a certain style of talk, about audio. It means something different in archery. That’s all we have to go on, but it’s enough.