The US (NIST) in collaboration with international bodies lead the redefinition of SI units based on fundamental constants [2]. Furthermore, semiconductor industry, university labs, medical industry, etc. all use ISO standards and the metric system. The US semiconductor industry alone is larger than the GDP of Switzerland. I studied engineering in America and we used the metric system throughout with some problems in ANSI units for familiarization of the units - ultimately, the engineer needs to adapt to the company's unit system and not try to be a thorn.
I personally am tired of the rest of the world patronizingly explaining the advantages of the metric system to Americans - over and over. It is not that difficult of a concept and most technical people, engineers I know in the US already understand the benefits of the metric system. It is mildly annoying at best and condescending at worst. If we are in the unit system mess, there are a lot of things that still do not follow base-10 based units. For example, font type units (points) from Switzerland. Or the way we measure time. How come there aren't 10/100th units of a minute/hour commonly used around the world? A second is split into 1000 milliseconds but a minute is not split into 1000 seconds. Why this inconsistency? Why 360 degrees? If we didn't have 10 fingers, the entire decimal system is worse than base 12 or duodecimal system [3].
The problems faced by America are exactly the same type of problems if we want to convert the entire world to duodecimal system. It is next to impossible despite of clear advantages. Note that I am not defending the people that arrogantly want to stick to status quo - there are certainly people like that in the US.
[1] https://en.wikipedia.org/wiki/Metrication_in_the_United_Stat...
[2] https://en.wikipedia.org/wiki/2019_redefinition_of_the_SI_ba...