Didn't France go metric a few centuries ago? Anyway, I suspect there are at least 10 times as many buildings, and 10000 times as many machines deployed, in 2026 America than the number you'd get by adding every European country's stats at the year they really seriously standardized metric.
You can make a better case that we were fools to not stay the course in the 1970s than a case that we should try it today. Even the 70s seem more like the very tail end of a window. 1776 would have been a great time to do it!
To some extent yes, but I just think it would be a greater hit to the overall GDP with more mechanised things in existence. Maybe I'm wrong, I just think that in the farther back you go, the greater the share of the economy that wouldn't be dramatically impacted by a metric changeover. Like, farming was somewhat a greater share of the GDP then than now, and a lot of goods are weighed and sold in bulk, not really all that hard. A farm would need to replace irrigation pipe and retrofit their scales, but not demolish and build new farms. A car factory, on the other hand... it would take a while for all those machines to naturally be replaced.
You can make a better case that we were fools to not stay the course in the 1970s than a case that we should try it today. Even the 70s seem more like the very tail end of a window. 1776 would have been a great time to do it!