Eh, it’s “hard” for the U.S. to switch from customary to metric units because nobody really cares enough to do so. The forces causing language standardization (in many countries, not just China) are much more powerful.

Americans use metric where it's required by law (e.g., food and drug packaging), it just takes government force. Government force can also change a population's language. See, e.g.,

https://en.wikipedia.org/wiki/Anglicisation

https://en.wikipedia.org/wiki/Russification

https://en.wikipedia.org/wiki/Sinicization

> I cannot imagine what it would take to unify a massive population under a single dialect

Ask French how they've managed to (almost) eradicate the Occitan and Breton and spread the Parisian dialect as the offical variant of French language throughout the country.

VTubers and ~15 years. Media, in generalized form. The velocity of weebs internalizing fringe Japanese concepts is astonishing.

Not as fast as the reverse. It's surprising how much Japanese is just borrowed English written in katakana.

It's worse than that, the US doesn't even use Imperial units, which was only introduced after US independence..

They use their own unique set of units that are different to both Imperial and Metric.

The US will be slower than most places due to the federation and ideological individualism.