The "copy" in copyright is there because of an accident of history: once upon a time, to "copy" was to do something industrial. Copying required physical plant, employees, premises, trading. While not everything industrial could be reduced to "copying," all copying was presumptively industrial. There were ways of non-industrially copying things – a sculptor could copy another sculptor's work by application of her eye and hand and chisel, a writer could dip his quill and set out the lines of another writer – but it wasn't really necessary to explicitly declare that this wasn't the kind of thing regulated by copyright. Such activity was almost always invisible to rights-holders, and even if an individual work happened to rise to the attention of a rights-holder, he would seem like a bit of a fool trying to apply industrial rules to individual actors. It's like asking your neighbours to register as a bed and breakfast because they've got guests in for the weekend who've chipped in for groceries.