People dont like change. So if there is not a great reason for them personally to change then they wont.
Local fruit and veg sellers here still cling on to ounces and pounds, refusing the change. Especially if they are of a more senior generation. Ignoring the fact that everyone under 40 have been taught metric since school.
Whip: The government could force a conversion but they will not get re-elected.
Carrot: You can gradually introduce it in schools, science, consumer products which is what is happening. Until people have grown accustom to metric and then to the last whipping change.
Cost: Secondly the whip will be unpopular even if converting to metric would mean more exports, more efficient manufacturing and engineering. That benefit is too long away and not personal enough for average Joe. He only cares if foxnews or equivalent will shout that the budget cost for this immediate conversion is X Billions. Irrespective of much large gains after X years.
As a person born and initially raised in an SI metric country but also lived the past 15 years in a imperial measurements country, I wish the last whipping change happens soon. I still convert miles into km (or roughly 2/3 or 50% more depending on which way). I still have no idea if im 5'8" or 5'11" but I know I am 1.75m tall. I know I am 95kg heavy, but never remember exactly how many stones or pounds that is.
Maybe that is metric snobbery but as a scientist I just don't see the point of imperial. It is frustrating to see the inefficiency and nonsense of it. Which usually means confusing conversations with my inlaws which are too old to have been taught metric in school and still refer to fahrenheit, ounces and feet for everything. Mentioning I need 2dl of milk or 1.5 hectograms of flour perplexes my mother in law :)
