We were almost there in the 1970s. As for "a few generations", yes, certainly. We have only to look to the mishmash of unit use in the UK. But what's wrong wi

We were almost there in the 1970s. As for "a few generations", yes, certainly. We have only to look to the mishmash of unit use in the UK. But what's wrong with taking a few generations to get there? Turning it around, we got rid of a lot of specialized units - hogshead, chain, furlong, peck, etc. (If Peter Piper picked a peck of pickled peppers, how many many more are needed to make a bushel?) So it's clearly possible. Also, metric countries still use non-metric terms for some cases, eg, "inches in a screen", the market price of a "barrel" of oil, and food energy in "[food] calories". This tells me that the transition can occur piecemeal.