In my opinion the objective answer to the question of identity is that there isn't one. "Identity" in my opinion is an arbitrary human concept, that only exists in our own minds. Whether two copies of a person are the same person or not is a matter of opinion, not fact; there's no "true answer" to find.
Or look at aluminum; it used to be a precious metal, but with better methods of extraction the value of an individual chunk of aluminum became quite small - but at the same time the aggregate value of aluminum in all its various uses is much larger, and has grown far beyond merely being used as rare ornamentation.
It can both decrease and increase value. A single molecule of water is basically useless, but a glass of trillions of them is something you can drink to save alive.Inflation would argue that more of the same thing devalues both however.
Or look at aluminum; it used to be a precious metal, but with better methods of extraction the value of an individual chunk of aluminum became quite small - but at the same time the aggregate value of aluminum in all its various uses is much larger, and has grown far beyond merely being used as rare ornamentation.