system
A chat on subreddit /r/NoStupidQuestions
human
In 1975, Congress passed the Metric Conversion Act and many companies thought it was just a matter of time before all products became metric, according to NPR's Marketplace. But the legislation stipulated that action was simply voluntary.

cola went with metric, milk didnt 

why did cola? well pepsi was tired of losing out to coke so they made their bottles bigger! 

milk had no such competition or reason to change
gpt
This was oddly interesting