Revisiting High School physics, the Second Law of Thermodynamics introduces the concept Entropy. Simply put, Entropy is the amount of disorder in a system. In any given system, Entropy can only increase over time, meaning disorder increases over time.
While the concept applies to Thermodynamics, you can see it at work every day. If you don’t dust your house on a regular basis, the amount of dust (disorder) increases. Roads age over time and form potholes that require patching and eventually, require the road to be re-pathed.
Development teams are not immune to the Trap of Entropy. If they are not actively trying to make themselves better, a team will move to disorder. This is one of the many reasons why periodic Retrospectives are so important; they help the team establish order and ensure the team is improving. Because if a team is not improving, the team is declining.