I figure copper is a good bet, because as Islam takes over Europe they will not quite measure up to the Iron Age.
Goldbug ping.
Copper aside, the thoughts expressed about what people want and will work for are if anything understated.
There are lots of electrons spent talking about exporting jobs. The jobs were not exported they were subcontracted to places where people work harder for lower wages. That is they are competing in order to have new and better stuff. Mo copper!!! they want more copper. Copper is the symbol of a better life
This market force is the reason the anomaly of total American dominance is no more.