In the USA scientists used metric starting about 1850 !! Nobody took the hint. In college they took fun in presenting a test with all the given data in different systems !! Inch decimal, inch fractional , cgs, mks.and anything else they could think of like Angstrom. When computerized machines came out I always forgot - do you want the data in inches or metric ? No problem the machine understands both !!!
Well there had to be changes since more women were becoming machinists the 'closer than a cunt hair ' was no longer PC !