Could not agree more. The point was to show just how many temporal and technical factors went into the development of a single (important) Game Technology. Nobody stood up in 1000 CE and said "We got Steel!" - it was a long process, and not at all the same sequence and process in different parts of the world. For any playable game, decisions have to be made as to what Point will be used for the Binary Choice: You have/have not Steel. Once you start adding granularity (I got a little Steel, I got a sort of steel, etc) the game dissolves into tedium very quickly. The larger point, though, is that the Technologies that are associated with Units in too many games (not just Civ!) are usually Wrong. Neither Steel nor Stirrups resulted in Knights, unless you accept that people had both but sat around and brooded about what to do with them for 500 - 1000 years. In almost every case, a military 'Unit' is a socio-political unit as well as a technological one: Knights, Hoplites, Legions, Spearmen, Swordsmen, Horse Archers, are all examples, but by no means the only ones. It would be nice to see that 'human factor' reflected in how the units are made available to the gamer.