Our cities are poorly planned, which makes it seem like they are congested, but they really aren't. It's just the cars.
It's actually good to have your population in cities, rather than spreading them out over the land across dozens of towns and smaller cities. By concentration people in cities we take up less space, which means we have more space for agriculture and wilderness.
Cities should also allow us to be efficient in terms of providing services. For instance, people living in cities have better access to hospitals that have specialist wards and expensive equipment. We can also utilise mass transit and medium-density housing to improve access to urban hubs and reduce car usage.
Unfortunately Australia has done a poor job of implementing mass transit, mostly because our cities experienced rapid growth after WW2 when people could afford to buy cars. Most suburbs were (and still are) designed around cars while buses and trains are an afterthought, and not much of one at that. The recently opened Rozelle interchange in Sydney is a fine example of how incompetent Australia is when it comes to solving transport problems: we are still trying to get everyone everywhere in cars. It doesn't scale.
On the occasions that I have to drive my car into the Adelaide CBD, the commute is hell. Not Sydney bad, but it's bad. The cars crawl for dozens of kilometres. It really gives one the sense that the city is choking. When I catch the train into the city I get an entirely different impression: the train ride is much faster than car, for one thing, and the entire commute, including the carriages, the station and the city streets give the impression of a city that is busy but not crowded.
Australian cities all have sprawling, inefficient low-density suburbia which need to be completely redeveloped to adapt to life beyond the postwar boom. More mass transit, more parks, more medium-density housing, more bike access, less car access.
