Switching from existing structures like parking etc to public transport? How? How fast? What do we do with that space? Who pays for it? I’m frustrated by the system but we can’t just start from a blank slate, we have to work with it.

Are you serious? I was in the US once, and within 3 days, I felt depressed. At least two thirds of basically any downtown appears to be parking and there’s at least a further 15% that’s overly wide roads.

You could remove the concrete and build parks which would improve those cities’ water household and have made me feel less depressed. You could build housing. You could build stores. You could build third places. You could make downtowns livable.

And it’s definitely possible. Because those places all existed before they were bulldozed to better suit cars.