> "Going metric" raises the question of whether we adopt metric measures for our existing standards (such as pipe threads) or actually adopt the ISO sizes.

You adopt ISO sizes FFS. They are international standards. You really want to invent a whole new set of incompatible 'standards'?

You think the US is the first to go through this? Australia, Canada, and the UK went metric in the 1970s (we also decimalised our currencies). Yes it was challenging for some adults but mostly pretty easy for kids. People adapted. Industries adapted. Now we hardly think about it except when dealing with Americans or in some historical contexts.