Broken Windows Theory
Visible signs of crime, anti-social behavior, and civil disorder create an urban environment that encourages further crime and disorder, including serious crimes.1
This theory can be applied to building software.
The existence of unmaintained (‘broken’) code can imply any new effort to clean it are undervalued. Developers following existing broken patterns in the codebase believe them to be the status quo. The result is no one fixes it because “it’s just the way it is.”