this is also the reason why it took until the industrial revolution for a wider used system to develop. Even before metric became standard, a lot of local measurements existed inside countries.
mass manufacturing required a system which would work outside the local sphere.
Good point. I think this story also interweaves practical and cultural elements.
The industrial revolution changed how measurement systems were used. It became important that a 13mm fitting measured in Paris was 13mm in Milan. Also, that age had novelty everywhere. Cobblers & weavers were separate worlds in medieval times. It didn't matter if they used different units of measurement. Novel industrialism required it.
On the cultural side, there was the French revolution. They wanted to throw out everything old and irrational. Old measurement units got the same guillotine treatment as old rulers. Tradition must die. This was the political and cultural environment that yielded the metric system. The political element also explains why the British Empire didn't adopt it.
The BE also needed rational units, ultimately. But, instead of adopting the radically rational metric system... they tweaked their medieval system into standard "imperial units." Why?
First, they weren't going to adopt their enemy's stupid system. Second, their philosophy was conservative. Tradition must live.
It's interesting how the ideals of the era (republican vs parliamentary monarchy) were mirrored in these decisions.
