There were people who foresaw, if not perfectly, how bad WWI would be, and tried to stop it. Many of them were socialists - Rosa Luxemburg and Karl Liebknecht in Germany, Jean Jaurès in France for example - and their final hope was that the proletariat of the European nations would not fight against one another, but we know how that turned out.

The problem was that there were not enough who were afraid, and that goes for WWII too.

There is also the view, which I think has considerable merit, which regards WWII in Europe as a continuation of WWI, and the Pacific war as a largely separate, though concurrent, event.