Who is talking about getting rid of suburbs or limiting things to walking distance? That would be crazy.
There were suburbs before cars existed and there can be suburbs that don't require cars for every single trip. Before the widespread adoption of cars, suburbs were often served by streetcars that let people travel into the city. They also were walkable for trips within the suburb. Unlike modern suburbs, they also allowed low nuisance commercial properties to be interspersed with residential properties so that many of people's basic errands could be accomplished without traveling large distances.
There were suburbs before cars existed and there can be suburbs that don't require cars for every single trip. Before the widespread adoption of cars, suburbs were often served by streetcars that let people travel into the city. They also were walkable for trips within the suburb. Unlike modern suburbs, they also allowed low nuisance commercial properties to be interspersed with residential properties so that many of people's basic errands could be accomplished without traveling large distances.