[So, where you draw the line? That's the basis of my argument. You just believe "there must be some point where identity cease to exists". My argument is that identity is fiction.
I have no idea where you draw the line, but things end. If I burn my house to the ground, it is no longer a house, if I get shot in the head, I am no longer a person. Existence is finite. Everything you think of as an object has an identity that makes it more than a collection of particles. If you destroy an object and put it back together, what you have is a facsimile of the original. A copy is a copy, no matter how similar to the original.
Perhaps a consciousness could be passed from original to copy, perhaps not. I don't even know if my mind right now is the same instance of my mind from a year ago or yesterday. I'll still take my chances with the shuttlecraft. I'd rather continue to be replaced one meal or glass of water at a time, not all at once.