As long as there are architects in the US, S.I. will live on. We (speaking for architects, since i'm not quite one, but have worked as a cad tech. for the past 6 years) will never change. And the US as a whole will never change until they start to teach it to kids in elementary schools. Of course they would have to teach both english and metric units. And once they start doing that, it'll take at least 2 generations to get used to it. But if it's not used in everyday life, then people start to forget metric. So that would mean that all the street signs would have to change, milage markers, packaging, etc. It would be way too expensive and time consuming. And americans are cheap and lazy, so in short, it's not gonna happen. Ever :~)