Parts of the video I've linked are very relevant to this.
Thanks Ken ,you would think though Aus population would have to eventually spread out further west as the years roll on ? Sydney itself is running out of room , though there is still a lot of land in the Far NW metro area of Sydney though thats slowly Filling up.Bit of a different case with the US @Gleno71
Compared with Australia, they have a higher proportion of land through the interior (e.g. the Plains States) where enough moisture regularly penetrates to make it relatively hospitable and fertile for people to live.
Sure, a reasonable chunk of that's taken up by farming, and there are still areas like the desert southwest region which are arid.... but if you've ever flown across the heartland from coast to coast, you'll notice how the population's fairly spread out with lots of farmland or even big areas of undeveloped land once you get away from the bigger cities. That's despite the total population being far higher than Australia's.
In contrast, most of Australia's population is restricted to near the E, SE, and SW coast and adjacent inland because a large proportion of the rest of the country is so arid and difficult to sustain a high population.
How large of a population could Brisbane handle? Will Brisbane eventually be house upon house from the coast to the Toowoomba range ?