Of course it could have learned something from the war, but it could also have learned from the Balkan wars. There isn't a anything stopping them from building more light artillery, light machine guns, training in indirect vs direct fire or using handgranades and trench mortars. Especially Germany , which was the first great power to adopt these weapons and tactics in 1914 and 1915. Every major power had sent observers (that later rose to command positions in ww1, like Von Etzel and Max Hofmann) and every country published accounts that varied in lenght and precision. The Germans even updated their infantry tactics in the 1906 drill Regulation manual, which specifically suggested the breaking up of military formations when necessary. So they did learn something at least, and certainly they didn't ignored the war. There was no major revolution in doctrine because such things are hard to accomplish, especially in fields dominated by the aristocracy such us early 20th century armies (even tho Republican France was probably the country that missed most of the lessons taught by the war, mistaking Japanese success against Russian defensive formations as another confirmation of their belief that a well motivated army could beat every defense). Also, your question is based on the common misconception that European countries were preparing for a world War in 1914, and that the schlieffen plan was an actual comprehensive plan to win the war. The Schlieffen plan lacked many details and basically focused entirely on the western front, ignoring Russia, some historians believe that it was just a way for the German military to get more funding. The point is that nobody was prepared to fight a great war in 1914, and nobody had a war in mind, except the usual hawks.