I have significant doubts that the U.S. will ever really convert. Although a few industries have, I wonder if we have already reached saturation.
That said, I really lament that SW was internally metric, instead of unitless. When I try to import a 1"x1"x1" cube in an IGES file into SW, it doesn't successfully import. Apparently the 1" dimensions were getting rounded at some point so that the sides were not parallel to each other.
Inventor really frustrated me with its poor handling of Feet-Inch. It felt like watching a foreign film that has been dubbed into English. I now learn that SW has some similar problems... defining materials library must be done in metric, regardless of your settings for english units. But, if you set a custom density for a part, that is done in english units.
As an aside, I think English units really are better anyway! The metric system seemed to be more politically modivated than adopted for pratical reasons.