As a general statement, I have noticed that we have collectively seemed to have forgotten all we once knew.
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Yep, I fear that we will see a time when we will need some of the knowledge that used to be so common but has been considered useless for the past two generations.
As manufacturing in the US continues to be exported overseas, industrial processes will be slowly forgotten as workers retire or die off. The documentation of defunct companies is eventually destroyed. There is no way we could re-industrialize quickly if countries like China decided to stop selling to us.