You can't wind rope that hasn't been dried and ret and dried again. There's too much "other stuff" in the fibers, and any rope you make will be incredibly weak.

Everything about this paragraph is confusing:

"The researchers managed to fashion 5 meters of rope in about 10 minutes with their replica batons. For fiber, they used everything from flax and hemp to cattail reeds—all plants that would have grown near the Hohle Fels and Geissenklösterle caves 30,000 years ago. The ropes proved capable of supporting the weight of one of the team’s larger members. Reeds made the strongest rope fiber."

Reeds make very poor quality rope without a lot of processing, and even then the fibers are very weak. In contrast, flax and hemp fibers are exceptionally strong. 5 meters of rope in 10 minutes would be a very crude rope indeed, unless they had a winding rig and all of the fibers ready to go. Cattail makes good rope, but like reed it requires quite a bit of processing because it's so fleshy.