Ok I did a little research and I found this article. In the spiritual sense Odysseus is a hero, because he remains faithful and loyal to his wife and household. Although he has been wandering away from home for almost twenty years, the only thing that keeps him alive is the thought of his wife and son that are back at home waiting for him.
the reason they do this is because when you are reading the story you dont want a 500 or 600 page book with 3/4 being about how he grew up the author thought it irrelivant