1) In most "urban" areas, all of the nearby land is already in use as either housing or businesses or public land. (parks/schools/etc..) There isn't any free space to just buy and build on, so you usually have to destroy something first. In order to build an apartment complex, you often have to buy and destroy multiple somethings. (like a small strip mall or restaurant, or perhaps a church)
2) Zoning laws are seriously wack, yo. Some places have zoned their entire area as single-family only, or 2-floor apartment limits, combined with complex housing/business sections. Melbourne did this with sometimes good intentions, but the 20 mile radius of a major city really needs a butt-load of apartment complexes and not single family houses... but the only ones that can afford to work through the zoning hurtles usually are aiming for high-priced luxury apartments only. (good business model for them, bad for society at large.)
3) People need to live where the work is, so you can't solve the problem by saying "move to the middle of bum-fuck nowhere."
99% of Australia is an uninhabitable Mad Max wasteland full of radioactive mutants, poisonous everythings, and ants that eat human flesh. The only survivable lands are cities run by pig shit near the coastlines. That's why Britain used to drop prisoners there, to watch them die. Most did. Those that survived the wastes became the rulers of the wastelands, building armies to try to defend themselves against constant attacks by the emu.
I live in a rural area inland. People have no fucking idea what its like. There is fucking nothing out there. Most of Australia is barren. 95% of all people live along the coast, and space is limited.
