There are lots of cities where you can choose to live in particular places to minimize car usage. You don't need to redesign whole cities (and thats the ask to add fast efficient public transit) to support that.

You can do localized changes such as tax incentives/penalties, subsidize parking less, zoning law changes that make it easier to mix businesses and residential etc.

That plus smart investment in public transit and a mix of ride sharing are all part of the mix to decrease car usage.