No, because not all land is desirable. You can save money by moving 500km away to an uninhabited place, but now you have a full-day commute in each direction,

No, because not all land is desirable. You can save money by moving 500km away to an uninhabited place, but now you have a full-day commute in each direction, so you can't go to work any more. How is that useful? People live close together because there's physical benefits to doing so, and the more you spread out, the more travel time increases. And because of the 2-dimensional nature of roads, you get a greater-than-linear increase in travel times as the city expands because of gridlock. You're also assuming there's lots of land in places that people want to live. There's plenty of empty land in the frozen tundra, but no one in their right mind wants to live in places like that. The places that have nice weather where people like to live also happen to be the places that are best for growing food.