>>515178467
I'm oversimplifying a bit, but our cities tend to be located in really good locations, where you have to build according to the geographical constraints (rivers, bays, etc.)

So you tend to have high density (i.e. skyscrapers) near really good spots.

We could technically build huge American-suburbs on empty flat land (and to some extent we still do have some of that sprawl), but no one really would want to live there.

People want to be close to the Sydney harbour, the beach, etc.