People won't accept being pressured to relocate into grim megacities while leaving the rest of the planet mostly uninhabited.
You could drastically revamp zoning laws and still living in the outskirts would be less expensive (See: Japan). Of course we should do this because it creates more options and opportunities for consumers and which NATURALLY increase density of cities without the need for senseless coercion.
Bothered by homeless people sitting on the street? A lot of them would rather be in a living room. Got mugged recently? While it doesn't excuse the mugger's behavior, they'd be less likely to commit the crime if their rent was dramatically cheaper. Don't want to listen to your neighbors arguing? Changing up the walls in your apartment building can help a lot.