If the 150 years of attempting to metricate the UK is anything to go by, it'll happen by legislation otherwise barely at all outside of industry. The UK had legislation permitting metric units since the mid 1800s (as did the US apparently). Full metrication was recommended around a similar time!

It was 1965 legislation was passed to fully metricate within 10 years. We taught only metric in schools since the early 70s. A huge publicity campaign and changeover began. Only the EU really pushed it along by requiring only metric measurements, since around 2000, on packaging with a few exceptions. The previous 30 years was a weird half hearted mix of units mainly down to where something came from. So now we buy a 454g jar of jam etc. There's no need for it to be 1lb, but it almost always still is. You'll still hear folks young enough that even their parents were only taught metric ask for half a pound of something at the supermarket counter. The shop then gives them a metric marked equivalent.

Youngsters still talk of weight in pounds, and height in feet and so forth but have never been taught imperial units. A good part of must be social (hearing on tv, from parents etc), but I suspect the human friendliness of imperial units, being generally coarser (6ft or 182cm, 454g or 1lb) and often derived from body parts, is part of the reason they still stick around so tenaciously.

The thing outside EU weights and measures, weed, is also still always in ounces and quarters! :)