The suburbs that contribute to urban sprawl (especially the ones that have been built since 1980) show that there is nothing but profit in mind for land developers. Many neighbourhoods are hawked as "products", with houses built so that if you've seen one, you've seen them all.
The majority of suburban neighbourhoods are built with a bias towards the car (you have to use a car to get anywhere), so that you are forced to contribute to air pollution, and the sprawl means that you have to make an incredible amount of emissions in order to get to the city centre.
Rural land and animal habitats are swallowed up as a result of urban sprawl, contributing to loss of food production and loss of biodiversity.
And do the developers care? No! They would pave paradise and put up a thousand parking lots if it made them money!
If they developed on brownfield or greenfield land, it wouldn't be as much of a problem, but instead, we get sprawl!
Don't buy into any of the nonsense about "urban sprawl." A lot of people prefer to live in a lower density areas with less noise and more privacy. It also correlates with lower crime and safer neighborhoods. Even the EPA admits lower density means less smog and congestion. This is an issue of choice and freedom. A lot of people prefer being able to raise their children with a lawn.
And last time I checked, only about 5.2% of the United States is what we'd call "developed." It is fear mongering to pretend all the land is vanishing, especially farm land. And as for the whole "car bias" argument, that can be defeated when you realize that people that choose to live in the suburbs because they also prefer driving.