If you think Como, Incheon or Reading are anything like Beverly hills, Brookline or Piedmont, then I'm not sure you're getting my point. All 3 of my examples a

If you think Como, Incheon or Reading are anything like Beverly hills, Brookline or Piedmont, then I'm not sure you're getting my point. All 3 of my examples are within 10 minutes walking/driving from the downtown core of the city. Yet, they have carved out a completely isolated township for themselves, so as to avoid taxation from the parent city, while benefiting from every aspects of being geographically inside the parent city. It stops a city from expanding organically, leading to oddly tiny cities (SF) or city boundaries that look like a kids scribbles (LA, Boston). If you city isn't propagating radially from the downtown core then there better be a good explanation for it.