Look at England. Or India.
It can be done. Easily.
I’m an American who hasn’t been taught anything Metric since middle school. I know that I weigh about 100 kilos, I’m a little under two meters tall, the speed limit is roughly 100 kph, and I’ve been buying soda in liter bottles my entire life. If we’re “the greatest country on earth”, SURELY we have the mental capacity to understand the metric system.