I think the way it'll happen is by America's loss of manufacturing. That's a big user of units and it's declining. Imported stuff is going to be more and more o

I think the way it'll happen is by America's loss of manufacturing. That's a big user of units and it's declining. Imported stuff is going to be more and more often metric unless it was also designed in America. So people are going to encounter it more and more. At some point, there might be a price penalty for specifying the less common imperial threads and material thicknesses on Chinese made parts so American designers in competitive industries might start preferring metric. But it might never go away from daily life. The Chinese still use "jin" as a unit of weight/mass. The communists unified the customary definitions to be exactly 0.5 kg, but even they weren't powerful enough to force everybody to use kg directly. If a communist dictatorship is too weak, there's no hope for a democratic government!