There is such a term called a “creeping normality”. The expression was coined by American scientist Jared Diamond in his 2005 bestseller, Collapse: How Societies Choose to Fail or Succeed. He had touched upon the subject earlier too “while attempting to explain why, in the course of long-term environmental degradation, Easter Island natives would, seemingly irrationally, chop down the last tree.” The concept is put succinctly in the Wikipedia entry on the subject: Creeping normality (also called...