Earlier quoted context omitted.
I'd strongly consider voting for a US presidential candidate solely on if moving to metric was a big part of their platform. So much time is wasted in school on the confusing mess that is the imperial system.
The amount of time and money to shift at this point would be astronomical wouldn't it? It would take a few generations as we would continue to have to teach imperial so people could convert when they ran across any existing media referring to the imperial system measurements. Hundred years of machines that use imperial, speedometers, odometers, books, tools, software, air conditioning, heating, manufacturing, constru…
And, in any case, most people have a mobile phone now which can quickly do unit conversions. I really think it actually is feasible, if you could get the public behind it (good luck).