Real world comparisons don’t help you here - creating a new digital document from an existing document is a very simple four step process. Duplicate, open, select all, delete. If it were that easy in the real world, perhaps we would.
Especially for things like letterhead or forms. Who wants to go to a room filled with thousands of different forms, if they could just get a fresh and clean one with four simple gestures?
It seemed to me that the author was claiming that people copy existing documents on computers only because it's the only (or easiest) way they know of to create a new document of a given type, not because it is actually the easiest way to create a new document of a given type. It seemed to me that the author was decrying the fact that so many people copy existing documents and delete all the contents, and was providing that as justification for why the New menu exists.
Especially for things like letterhead or forms. Who wants to go to a room filled with thousands of different forms, if they could just get a fresh and clean one with four simple gestures?