> How do we even fix car-dependency in the US?
Car-dependency is a city planning issue, first and foremost. We destroyed the cores of our cities, demolishing block after block of buildings to raise interstates and parking lots.
You will never eliminate car-dependency in rural areas, and you can at best remove the need for it in suburbs with mixed-use zoning (i.e. corner stores and cafes), better funded public transit, and sidewalks.
Cities should first stop expanding interstates and look to remove them entirely. There is absolutely no need to have an interstate through urban cores. Next, you need to redesign streets to make the car part narrower and the sidewalks wider. And you need to repeal zoning ordinances that ban anything but single family homes on 80% of urban residential land. It's ridiculous that there exist single family homes within walking distance of the downtown of cities with a population in the millions when under a properly zoned system, there would be mid-rises.
Rural areas will never be free from car-dependency. Suburbs need light modifications to mixed-use zoning policies and transit, as well as infeasibly high taxes. Urban areas, where walkability should be most feasible, have to remove highways through cores, repeal oppressive zoning laws, and prioritize walkability.
The actual policies are rather straightforward. There are plenty of countries that planned around the automobile and later reverted this mistake, so there exist many playbooks for achieving this worthy goal. Unfortunately, the problem is political rather than technical: too many people are invested in the automobile for a lot of good reasons, and too many people are invested in the current land use regime which make automobiles necessary.