Most East Coast American cities have neighborhoods that were built 100 years ago as suburbs because it was impractical to walk to downtown that are now consider

Most East Coast American cities have neighborhoods that were built 100 years ago as suburbs because it was impractical to walk to downtown that are now considered inner city. Other areas of the country do as well, but I'm only speaking to my own experience in the Mid-Atlantic. These neighborhoods are higher density than modern suburbs but much lower density than downtowns. People like the character of these neighborhoods because they seem to offer a good mix of being centrally located but still quiet and pleasant. The people who live in them try to keep that character through zoning and NIMBYism. This is a compromise to preserving what the residents like while allowing slow increases in density. A reasonable next step would be to allow duplexes and triplexes up to a certain density like 2 per block or something. That way the neighborhood could develop over time without causing the outrage that tends to accompany a developer getting a variance to throw up a modern boxy 4+ story apartment/condo building in an otherwise 1-3 story neighborhood.