As we become increasingly global in our everyday dealings, differences in units of measure become more obvious. The push for U. S. adoption of the metric system has been going on for generations. It will probably never happen — at least officially — because no administration will want to have to force multiple industries to bear the tremendous cost of converting to metric measurements. In fact, I think it would be more likely for an administration to introduce legislation declaring English as the official language of the U.S. — a move that would actually save money by eliminating the costs associated with producing government documents in two languages. Most industries would also benefit from such a move.
I was recently reminded of all this while traveling through New York and Massachusetts. In most states, mile markers on interstate highway exits are numbered according to the preceeding mile marker, so it's easy to tell how far it is between exits using simple arithmetic. However, exit numbers on interstate highways in New York and Massachusetts do not coincide with mileage markers — they are simply numbered sequentially, with no regard for mile markers. So if you've just passed exit 15, you have no way of determining how far it is to exit 16 — it could be 5 miles or 55 miles.
Standardizing on exit numbers should be easy and relatively inexpensive — at least compared to switching to the metric system. So if it is so difficult to standardize on exit numbers, it must be wishful thinking to expect governmental endorsement of the metric system in our lifetime.
I can't resist pointing out, however, that the fluid power industry standardized on universal symbols for circuit components more than 40 years ago. The standards are updated regularly, and fluid power schematic symbols truly have become a universal language. If you draw a regenerative circuit or meter-out circuit, you can communicate this to other fluid power system designers, no matter what continent they are from.
If we ever do adopt the metric system, I'm sure it will result from the accumulated voluntary actions of individual industries — much like the fluid power industry's adoption of standard symbols. If so, it would happen the same way you'd eat an elephant — one bite at a time.