Hello Abshalom,
First let me say that I am not trying to establish oral Mesopotamian myth or fact with message 14. I think there is no way of doing this. However, if the scribe thought that he was preserving or creating the history of his people I don’t think he would view it at as being laborious. I think you are correct in that the story was passed to the next generation by word of mouth until someone put it to pen.