Prussian imperialism was failing from 1914 when they failed to reach Paris and force France to surrender. Moltke the Younger recognised this at the time, but it took 4 years for rest of the German High Command to see it, and for the Allies to get their act together. Even if the German spring offensive in 1918 had succeeded, it would have only pushed the British Army back across the Channel, it wouldn't have stopped the British naval blockade which was crippling Germany, nor would it have stopped the build-up of US troops in France.
Agree, Germany lost WW1 when they failed to capture Paris and kick France out of war. And they lost WW2 when the same happened with the USSR at Moscow. That being said, the Entente got their act together as fast as Germany and Austria did in WW1. Without means to break static defenses, the stalemate at the Western and Italian fronts was a certainty, in hindsight. Wars of movement, in the East during WW2 went rather well for Germany. Especially after the shipped Lenin there, but this isba whole bunch of different cans with different worms.
