As I see it, the problem is that for the vast majority of people in the U.S. there is no compelling reason to change. People rarely need to convert units and rarely (but more often thanks to social media) need to talk to anyone who uses metric. I see it as a cultural quirk not unlike a dialect.

Of course for science, industry, and other situations where conversion, accuracy, and international communication are involved it very much matters and U.S. needs to use metric as much as possible.