[vvpan]

Some places derive their identity and tourism income largely from how they look. Building could be slaying the goose that lays the golden egg.

[embedding-shape]

Also, some places physically cannot grow outwards anymore, either because other cities are in the way or because of geographical elements like mountains being in the way. Barcelona is one such city, with one of the highest population density per km2. Only way is to build taller buildings, but no one wants to live in a city where you can't see the sky (ya ya, except Hong Kong and other places, don't ask me how they do it).

[FabHK]

Quality of life in HK is quite high, btw, plenty of green, parks, and sky. (However, no cycling in the centre, only the outer areas or islands.)