Part of the problem is the middle of housing was often in towns anchored by one or two factories or other local businesses. With businesses being hyper-centralized today due to the internet and technology decoupling business from land, employees are now located much more centrally (we'll see how remote work changes this). For example, Google has hundreds of thousands of employees in the Bay Area alone. That's crazy. In the past, this would have formed several towns all across the country (because Google would need such a footprint to be able to deliver services nationally).

Now that anyone can start a large company without barely any land investment, it's no wonder people are increasingly concentrating in small portions of the country, while large portions are incredibly cheap, and in some places, depreciating.