Aren't the materials to make rare-earth magnets... not actually that rare? It's only rare in the sense of their dispersal in the earth's crust, this making it a rather dirty and ecologically disruptive activity sourcing them. The US could theoretically start producing rare-earth metals, couldn't they?
Yes, but it trivializes the issue. You might ask why colonies needed to import finished goods from the motherland when they had all this wood and iron available.
