Why does this happen? Economy explains most phenomena. a) Developers want to maximise profit: generally more area means more profit and optimizing the height o

Why does this happen? Economy explains most phenomena. a) Developers want to maximise profit: generally more area means more profit and optimizing the height of the building is the way to get it. b) City Halls will evoke (sometimes dubious) historical value to block the old building. c) Developers will finally apply for an extension of the existent. City Hall has a tougher job to justify blocking the extension. After some delays, developers eventually will build it. Other fact to mix: extensions are probably the most demanding projects. Pragmatic architects (the ones that usually get large projects) are not suitable for it, they will not spend more time than the strictly necessary.