Look up events like the Bronze Age collapse, where a handful people disappeared and took a whole civilization with them. If knowledge and access is more distributed we can avoid similar loss in the future
Trade collapse led to impossibility of making bronze weapons, which further amplified collapse. This was possible because tin mines were few and far apart. So it was a vicious cycle triggered by a weak point, on a background of hardship. The lesson is not to depend on a single failure point.