What I took away from “The Lever of Riches” was a sense that the Industrial Revolution was inexorable. Living standards were probably stagnant – more on this later – but the technology was not. The simple answer to “why couldn’t have an Industrial Revolution happened during the Roman Empire?” was that not only did the technology not exist, but the years and centuries worth of prerequisite technology did not exist. The Roman works were feats of organization, not technology.