My Jeep is a bizarre combination of metric and SAE. ISS needs to have two sets of tools[0]. NASA lost the Mars Climate Orbiter due to confusion over the units of measure[1]. Patients are given the wrong dosages[2].
It seems safe to say it's a point of ongoing friction, especially on things like international trade.
I already made it clear that I totally agree metric should be standard in engineering or scientific applications. I wasn’t aware that this isn’t the case in the US — thanks for the info. I believe it is at least 95% the case in the US and I think we should make every effort to get that to 100%.
I still stand by my argument that it does not matter much for everyday life.
Well, the point I was arguing was "why not" have two separate systems ?
As for "why" to have them, well there isn't a good reason intrinsically -- if there were a way to magically convert the US to metric overnight, it wouldn't bother me. It just seems very unlikely and difficult in a country as huge and culturally diverse in the US. Especially since, by the standards of the rich/developed world, the US is pretty poorly educated, and also very difficult to govern (Obamacare, a law that would have seemed like a moderate reform, relatively simple to pass in any parliamentary system, is the most radical change in any area of policy enacted by the US federal congress in the last decade).
The thing a lot of people miss about the ultra-gridlocked US system is that there's a huge gulf between it being obvious to most people that "we should enact some policy" and anything actually changing. The best answer to "why doesn't the US do this or that" is often just "its political institutions can't".
Since it's so unlikely to change, and given my argument that it isn't a big deal in practice, I guess my main point is that we rationally-minded people should stop worrying/complaining about it so much.
I still stand by my argument that it does not matter much for everyday life.