Anthropology

which makes a lot of sense, getting your dinner home on a single travois is just not going to work unless you can manage to make some rope, and once you've accomplished that, you're well on your way to spinning a wide variety of fibers into a vast array of different weights.

Third millennium BCE is actually pretty late when you're discussing gear for textile arts, square into the Bronze Age. The earliest representation of a sail on a ship (which would have meant a large surplus of woven cloth was available) was on a Kuwaiti potsherd from the mid 6th millennium BC. Likely it was reasonably old tech even then.