I am 62 y.o.. I remember when my school district announced we would all be converting to the metric system soon. That was almost 50 years ago. It's a great example of human resistance to change and switching costs. I suppose it would be more efficient if the entire world adopted one common language too. But heck, we can't even agree on which side of the road to drive on.
Of course, the left side of the road is the right side of the road to drive on. (Maybe this sentence is a good reason why the one common language shouldn't be English...)