Measurements relevant to electricity are a fairly new phenomenon and the pioneers who worked on it mostly impacted the entire world. Similar to how the "decibel" coined by Bell Laboratories is named after Alexander Graham Bell, and at that point the international community was on board with keeping up with the latest research relevant to modern technology.

Humans have been doing things like walking to market and baking bread and weighing witches to see if they'll float for a very long time. There was no international community to manage those measurements.

Then the French and the Europeans and the communists came along with the metric system and Americans said screw you all.