Threshold and acceleration in output per worker
Labor productivity (output per worker-hour) climbed slowly for millennia. A medieval farmer produced barely more food per hour than a Roman farmer; a craftsman in 1600 worked at similar pace as one in 1300. Then, starting around 1750, productivity began accelerating. Steam-powered looms increased cloth output by 10-fold per worker; mechanical harvesters did work that took days in hours; factories coordinated large teams toward single goals.
This acceleration was self-reinforcing. Tools produced more tools, factories could build better factories. A worker in a modern plant produces hundreds of units per day that would have taken artisans weeks individually. This is the productivity explosion that powered the transition from survival agriculture to disposable abundance.
Geography of mechanization and capital
Productivity gains concentrated where capital invested in tools and infrastructure. Britain's textile mills, then American factories, then German precision manufacturing became global productivity leaders. Nations that remained agricultural faced a choice: mechanize farming (reducing farm labor but raising food output) or stay poor.
The productivity gap explains the modern wage gap. A factory worker in Switzerland earns 20 times an Ethiopian farmer not due to superior intelligence but because Swiss workers operate $500,000 of machinery while Ethiopian farmers use hand tools. Closing this gap requires capital accumulation and training, a decades-long process that most developing nations are still undertaking.