Berlin also has the advantage of only becoming a large single city in the 1920s. Beforehand, there was "Berlin proper" and a number of cities nearby nearly equally large and locally equally relevant (e.g. Charlottenburg, Wilmersdorf and Spandau in the west, Köpenick in the southeast and Lichtenberg in the east). Due to there being no cars, travel between those cities was impractical on a daily basis up until the rise of mass transport. This lead to these cities setting up their own city centres with residential areas formed around those city centres.

After extension of the city of Berlin in 1921, this lead to it having many "city centres" around which life was formed in a similar way Sydney attempts to achieve now by this artificial after-the-fact split. I’m doubtful it’ll be successful.