Given a factory from each era that produces roughly the same product and quantity, how many are employed at each? What are their inflation-adjusted wages?

It seems difficult to believe that modern factories can employ enough people for your blue collar middle class dreams to become reality. The difference in population alone is 200M vs 330M. And even modest improvements in automation has the modern factory at something like half the personnel of the 70s-era factory for the (roughly) same output.