I can't speak for all of US but at least in Midwest, in the circles I grew up it has always been an attitude or US vs the rest. Mention the metric system to a construction worker and he'll tell you to get the hell lost. US culture values individual accomplishments and self-direction so there tends to manifest an us vs them mentality. Having a unique measurement system helps support that mentality so I really don't see any change coming any time soon in regards to switching to the metric system.