Try this out. Have the government mandate that everyone buy a certain type of car/van. Tell them it's good for the environment and give them tax incentives to do it. Then, years after everyone's invested in that type of car/van, have the government ban that type of car/van in major urban centres. Tell them to throw the car/van away and buy another one.
And tell them that if they don't do that, you'll fine them every day, when they drive to the place they've been driving to all their adult lives for work, etc.
Announce that this applies to everyone at the same time, so there's near-zero resale value in the old type of car/van, and there's massive demand pushing the price up for the new type of car/van.
Most people don't have a spare £20,000 kicking about, and if they did, they wouldn't choose to spend it on that. Throwing away their existing car/van and buying another doesn't give them £20,000 of value. It gives them £0 of value. They already had a car/van. It might give some kids' lungs value, but not them.
Honestly, try it. Try forcing millions of people into spending a lot of money all at once, and see how popular you are. Bonus: now try blaming social media or some other fifth column for your unpopularity!