"Almost every" is a very strong statement. But even granted that, the interregnum periods (civil wars and revolutions) tend to be so horrific that they are wise to avoid. In fact, people like Plato, Machiavelli, and Hobbes who lived through revolutions tended to come to the cynical conclusion that any system of government was better than a civil war. I don't agree with that conclusion, but I'd rather see the system reform itself than jump immediately to "tear up the constitution and start over"