Also:
German explorer Alexander von Humboldt was the first Westerner to observe the unusual rope system in 1804.
So, in 1804 the natives were making hemp ropes half a mile long and using these for transportation? And (I suppose) had worked out the mechanism to maintain tension and a pulley system for return trips. That surprises me.
Rope bridges have a VERY long history in the Andes. The Incas used them extensively. Andean civilizations were probably the most rope/textile oriented in history. Even their system of writing was encoded in knotted ropes.