* once you force everyone to stop driving

There is no force stopping anyone from driving. The vast majority of roads allow cars, nearly every single home will have one or more parking spots. If you want to do everything by car, you absolutely can!

But once other modes of transport are viable, there is just no need to drive that much.

Kids going to elementary? A five-minute walk. Kids going to high school? A 15-minute bike ride. Same for sports, friends, and basically everything else they do. This means they don't need to be ferried around by parents all the time and they don't need their own car at age 16. With some minor infrastructure changes, the roads will be safe enough to do this on their own! This eliminates a part of car traffic, so you actually need less space for infrastructure.

This applies to adults as well. There's no need to drive to work if it's a 15-minute bike ride. Grocery shopping? Well, you pass a store on your way home, so just pick up the ingredients required for that day's meal.

You can still do it the American way and drive everywhere, but not doing so is suddenly an option too!

You don’t even need to force everyone to stop driving. Once density increases, distances get easier to cover by bike or by walking, adding policies that make people liable for the cost of space to put a car (ban or realistic fees for on-street parking) people will reconsider owning a car. Basically you can still drive - there’s still roads, but you need to stash your vehicle on your property. And then people will start considering whether they still want that garage or maybe a bigger flat would be cool, too.

> there’s still roads, but you need to stash your vehicle on your property.

Yep, just took a little Google Maps trip around Layfette, just another US town where people park on the street because we have more cars than we can handle or our garage is full of Chrsitmas decorations.

That's ridiculous. There are plenty of people driving even in dense towns.