It did get rid of a few of Europe's absolute monarchs and kept the constitutional monarchs that shared power.
The question I always found interesting about WWI, the interwar years, WWII, and post war years is "Why did WWI, which was called the war to end all wars at the time set the table for WWII just twenty years later while WWII has resulted in eighty years of relative peace among European countries?"
What did we get right after WWII that we got wrong after WWI?
The two events are close enough that you can compare and account for most of the social, economic, technology, and political differences and similarities.
I think there is an important lesson somewhere in there humanity needs to learn.