Why hasn’t the United States adopted the metric system for widespread use? I’ve generally thought there were two reasons. One is that with the enormous US internal market, there was less incentive to follow international measurement standards. The other was that the US has long had a brash and rebellious streak, a “you’re not the boss of me” vibe, which means that there will inevitably be pushback against some external measurement system invented by a French guy and run an international committee based in a Paris suburb.
However, Stephen Mihm makes a persuasive case that my internal monologue about the metric system is wrong, or at least seriously incomplete, in “Inching toward Modernity: Industrial Standards and the Fate of the Metric System in the United States” (Business History Review, Spring 2022, pp. 47-76, needs a library subscription to access). Mihm focuses on the early battles over US adoption of the metric system, waged in the 19th and early 20th century. He makes the case that the metric system was in fact blocked by university-trained engineers and management, with the support of big manufacturing firms.
This is not a battle for today. At some point the US and the other outliers will embrace the metric system. I drive friend, family, and SO crazy with my adherence to matrix measurements (and 24-hour clocks) where I can.