This is coolbert:
As extracted from the Professor Al Nofi CIC # 442:
•"The German Army entered the Great War [World War One] with some 33,000 regular officers and about 40,000 reserve officers, but upon mobilization required 119,754 officers, which meant there was a shortfall of about 42,750 right from the start of the war."
•"All of the officers holding corps, army, or higher commands in the German Army in 1914 were nobles, 77 percent of them with lineages reaching back to the Holy Roman Empire, and rest with titles created since the foundation of the 'Second Reich' in 1871."
The Schlieffen Plan as approved in 1905 was predicated on an expansion of the German Army by 50 % in troop strength. This the Kaiser did not approve of as that would have meant many more officers to be designated from among the commoner instead of the nobility.
That right wing of the German advance in 1914 not violating the territory of Holland and not sweeping and wheeling to the west of Paris as was the original intent.
The Schlieffen Plan might have worked IF the size of the German invading force was increased 50 % beyond what was the case in 1905 but a hesitant and reserved Kaiser not willing to confer officer rank on too many commoners.
More than anything else German planners making excessive and ill thought out demands from the enlisted man. Continuous marching without respite combined with the rigors of combat, too many troops too worn out by the time of the final climactic battle [First Battle of the Marne].