You've got it the wrong way around - expensive areas (usually because of lucrative local jobs) densify because it's how you can still turn a profit despite expe

You've got it the wrong way around - expensive areas (usually because of lucrative local jobs) densify because it's how you can still turn a profit despite expensive land. Cheap, poor areas don't densify because the land is cheap, and the way to turn a profit is to build big houses that can still attract some people.