Firstly I don't see why you need a loom to make a simple rope. People were making ropes before looms came around. However looms could be used to make a stronger type of rope, example Reinforced Rope, to be used for more advanced structures and objects. With the normal rope being able to be produced without any structures you could give it more uses than just Sturdy Sled and Cart. For example early house designs.
http://www.neropes.com/resources/history_of_rope.pdf