The revisionist countries’ decline after World War I did a great deal to prevent any major international conflict in the 1920s.
In later years, it was the unhappiness of the revisionist countries that caused World War II. Right after WWI, however, these countries (Germany in particular) were not in any position to cause major conflicts. Germany was devastated by the war. They no longer had the military or the economic power to cause conflicts in Europe. Italy was in a similar situation because it was experiencing a great deal of social and economic upheaval. Japan experienced much less of a decline. However, at that point, it was not yet as alienated from the world order. It had much less reason to be upset in the 1920s.
As we can see from this, the decline of these countries (particularly Germany) had a great deal to do with the lack of major conflict in the 1920s. However, it was not the only factor since Japan remained relatively content during the 1920s.