I remember when Mr. Carter was assuring us all that the metric system was the wave of the future and that it was imperative that we all learn it as soon as possible. I remember it being fairly simple to learn in -- whatever it was -- sixth or seventh grade. And then I remember it simply disappearing. Ol' Jimmah was wrong, it turned out, and Americans did what we do best, which is to do whatever we want and expect the rest of the world to deal with it . . . or not, as they see fit.
It's hard to change things people are used to. As you probably know we've changed currency 14 years ago. From Dutch gulden, German mark, French franc etc. to the euro. It's taken years for a lot of people to get used to it and put their old currencies (and their exchange rate with the euro) in the past. I think it would be a similar story when you would start to use metres, kilograms, Celsius and bar.