The metric system would most likely be utilized if it wasn't for the actual cost of converting.
Whether it be something for school like rulers, or something for the general public, such as road markers. Over all, it'd cost quite a bit to replace. Imagine every mile/hr sign having to be replaced by kilometers/hr. Every exit ### 2 Miles away having to be changed. It'd be a very slow and pricey conversion. Otherwise I'm sure it'd be embraced fairly quickly.