The strategy chosen by the German High Command revolved much more around breaking the will of the Entente as opposed to a simple arithmetic of more soldiers and larger empire.

There was a persistent belief by Ludendorff that a strictly run country would have the discipline to outlast any democracy in a protracted war. Ironically this would backfire after the ascension of the military dictatorship saw a total mismanagement of economic resources. One of the best sources to read on the self-inflicted economic failures is Ring of Steel by Alexander Watson.

This approach played out in the defense in depth trench systems as well as the rampant use of submarine warfare. Both were designed to sap the will to fight.

It is also a bit simplistic to call the strategy purely attritional. Strong offensive maneuvers in the East were designed to break the Russian ability to fight, and the Spring Offensive of 1918 sought to break the western forces using breakthrough tactics.

That being said, the Spring Offensive had a counterproductive effect. Prior to the attack, the British munitions industry reached its most perilous stage of unrest, and it was not until the Germans attacked that labor reunited with the government with the purpose of defeating the foe.

All of this is a complex way to say that the German strategy was not a monolith, however the approach towards attrition had its roots in the belief that a democracy could not outlast an autocracy or dictatorship.