[gregmac]

> As the neighborhood becomes denser, rents might go down, but land values will go up, since a given piece of land can now be used to build a more profitable apartment building.

You're taking about the wholesale destruction of neighborhoods, as they are, to be replaced with something else. The land value might go up, but the existing house value goes down, especially halfway through such a project. It's one thing if you're replacing low density multitenant buildings with higher-density ones, but it's a totally different story if you're replacing detached, single family homes. Usually the latter only happens after a decade or 3 of neglected, low value homes.

Higher density brings pluses and minuses.. more businesses, transit and other services, but also more traffic, crime, noise, etc.