It's not too late. Cities are constantly changing and reinventing themselves. Many cities have old industrial areas that are being converted to other uses, or very low density residential spaces that are being rezoned to higher density. Any time a neighbourhood undergoes change there's an opportunity to do it differently.

Vancouver's Olympic village (built from old industrial land) is an example of a brand new neighbourhood in a North American city built close to this form. It's not pedestrian only in width, but the streets through it are only a single car width wide.