True, a new hope was made to be a stand alone movie, but the point of the prequels were to lead into the original trilogy so that we know how everything came to be, it isn't suppose to conclude till the resolution in Return of the Jedi. However, since the second trilogy was made first, it was unknown if the first would be ever made due to budget at the time of filiming the original Star Wars, so it had to be made to stand alone. That's just my commentary.