America Has Been Struggling with the Metric System for More Than 200 Years

It's not even a 'struggle'. The truth is that whatever system a society uses for its measurements in daily life does not matter, as long as they are consistent. It is perfectly fine to have all of science and medicine using metric while people use miles and gallons in daily life.

Whenever someone decries that the US has not adopted SI, they always do it with a sense of "oh my gosh, just look at how backwards we are", without ever realizing how much we actually have adopted metric.

Sigh! --if you do eventually adopt the METRE, can you at least spell it properly.

It would be okay if we'd only just start using it. Having lived overseas for a couple years, your brain adjusts after a short time. Sigh.