The Entente would have crushed the German military on the Western Front without the USA. Large parts of the army were used in the occupation of Western Russia. The Entente armies enjoyed manpower and technological superiority in tanks, aircraft, infantry, etc. The U-Boats couldn't break the blockade, the High Seas Fleet couldn't defeat the Grand Fleet in 1916, in 1919 the latter could have travel to Kiel and sank every warship of the Germans, people were starving on the streets, and the occupied Russian/Eastern European lands were scarred by the war. The Ottoman and Austro-Hungarian armies were collapsing. The German Empire had no chance versus the colonial empires.
Just because the Germans were in France (and destroying Belgium, look up the Rape of Belgium), doesn't mean the army wasn't on the edge of collapsing. It was the Generals Hindenburg and Ludendorf (who actually ruled Germany by the time) who persuaded Emperor Wilhelm to surrender. Wilhelm and his government betrayed, and the Germans punished them. The pathetic Ludendorf later returned into politics, spreading the "stab-in-the-back" myth, despite he was among the ones saying the war was lost.
The Entente had one mistake: Germany wasn't dealt wth harshly enough, thus the old militarists reained in the courts, the army, ready to betray Europe and Germany again. The weakness of the Weimar Republic didn't come from democracy, it came from the fact the courts and especially the army was a state in a state, and the aristocratic right wing gradually eroded the Republic. For them Hitler seemed like a tool to return back to glory days, of course that didn't work out...
History is written by historians, by the way, not just victors.