@DeltaWye

Based on what happened in Britain - it will take at least 3 generations maybe more and there will need to be a firm educational policy forbidding the teaching of customary units in schools. There will also need to strict labeling regulations - old habits die hard.

I have spent much of my life living in countries where no one has the first idea what british imperial or US customary measures even look like, so I neither use nor think in 'old' measures - in fact I don't even use them in figures of speech in English these days.