[rm445]

Yes, that's the core of the issue. The US is a big monobloc, an economic superpower with not only the most advanced economy but also a lot of the history tied to developing the world's industries.

Other places saw more benefit to adopting SI units either because they were smaller and closer to lots of other places with a need to harmonise, or playing catch-up. My own country, Britain, falls in the first group - though the population still uses some everyday old units, it didn't manage to be a hold-out despite its historic position and industrial heritage.

It's hard to see the position being static in the longer term though, particularly if world economic growth gradually leaves the USA with a relatively smaller slice (in absolute terms much bigger, but a smaller proportion) of the larger future world economy.

[engi_nerd]

I agree. The only way things in the US will change with regards to standards like this will be if it becomes excruciatingly painful to continue being different.