I find a similar analogy in the idea of the bronze age vs iron age. It's not as if people in the bronze age didn't know how to make iron or even steel goods; bu

I find a similar analogy in the idea of the bronze age vs iron age. It's not as if people in the bronze age didn't know how to make iron or even steel goods; but it was really, really damn expensive. It just wasn't cost effective until they found new methods of production and/or new energy sources to fuel those methods of production.