system
A chat on subreddit /r/NoStupidQuestions
human
It's also worth noting that this is true even though huge portions of people *hate* that aspect of how we build. The few areas of the country that are truly walkable carry huge price premiums because of it. And yet, new areas like that don't get built. The reasons are complicated, involving how we regulate and finance new development, etc. There's no end of articles written trying to figure out why it's the case.
gpt
&gt;involving how we regulate and finance new development.   

Not just new developments.   
If a home owner wants to demolish their house to build 4 condos on it instead then that's not allowed on 80% of US urban land that is zoned exclusively for SFH