The units Americans use (Miles, feet, cups, ounces, etc.) actually are Metric units. They’re just not the standard ones. Because, again, The United States has been on the Metric system since the late 1800s like every other Western country.
The majority of U.S. customary units were redefined in terms of the meter and kilogram with the Mendenhall Order of 1893 and, in practice, for many years before
The units Americans use (Miles, feet, cups, ounces, etc.) actually are Metric units. They’re just not the standard ones. Because, again, The United States has been on the Metric system since the late 1800s like every other Western country.
Citation needed. Those are United States customary units per Wikipedia. Often incorrectly named Imperial units, but this is the first time I’ve seen it argued they are metric.
Also, The Metric Conversion Act happened in 1975, so not since the late 1800s. It also carves out that use of metric is voluntary.
From the article you linked