The 4th Industrial Revolution Is Coming: Hype or Reality?

The first is that human labor cost must exceed the cost of purchasing and using the alternative technology. In Roman Alexandria the cost of employing humans to do manual work was very low, a reflection of the fact that the supply of labor was much greater than the demand for producing goods and services. It was a lot cheaper to pay someone to do something, or indeed to buy a slave, than buying and using one of Hero's steam engines. In 18th century England labor costs were rising as more hands were needed to keep up with the global demand of goods, particularly as England, and soon to follow Europe, established trade posts and colonies around the world. Fast forward to the 21st century: for the past few decades the world economy has enjoyed low inflation and global growth thanks mostly to China, and the millions of Chinese workers who migrated from the rural areas to the urban cities and started working on factories.