Hugeness maybe not, but highly developed internal market always helps. One of the overlooked factors that the author mentions briefly is metallurgy. Better met

Hugeness maybe not, but highly developed internal market always helps. One of the overlooked factors that the author mentions briefly is metallurgy. Better metals translate to better machines. Even today, quite a lot of our technological effort is stymied by metallurgy. For example, China still struggles to develop a reliable jet engine for its fighters, and it took a lot of time for SpaceX to stop Raptor2 combustion chambers from melting in the heat. (IDK if this has been fully solved actually. But they are conducting static fires.) A steam engine needs to tolerate a lot of pressure. Ancient metals couldn't do that.