I'd wager it was Hindenberg and co's plan to cement power under themselves, as most of the Army was loyal to the Kaiser (something that the Field Marshals blatantly lied about), and the socialist forces would have been supressed earlier if the Germans (under Hindenbergs plan) hadn't decided to try to invade France just as the Americans arrived. after that assault failed it broke the armies morale, causing a mass rout; while the garrisonless cities were basically taken over by armed socialists just like in Austria & Hungary.
Really Wilhelm should have just courtmarshalled them, partially for their own incompetence, and also for subverting the power of the Kaiser over the course of the war, refusing to tell him what was actually going on, basically limiting him to a ceremonial leader, giving commands in his name, without even telling him what they were or entailed; censoring almost all information from the front - rerouting his own surprise inspection of the front lines to make sure he never actually saw the appauling conditions under which men fought in his name; lying about the threat proposed by enemy powers for their own ambitions (like telling him to take the Schlieffan plan, even though he was advocating for the Ost-plan, because he unlike his generals, actually understood the threat posed by Russia), ignoring his own actual understanding of his fellow monarchs (and very spot on paranoia) and their governments, and isolating him away from positions and offices he was actually good at managing , such as technological innovation, logistics and infrastructure.
These Idiots weren't even using captured foreign lands for German food and resource productions, with Hindenbergs own plans being so stupidly applied that they forgot to expand enough coal mines, and produce enough trains, so that by 1917, when they actually started doing something about their original problem, they couldn't supply the army, infrastructure and civilians enough, whereupon he decided to let the cities starve in exchange for his ludicrously (like Goering levels) mismanaged supply program. This of course made worse by the fact their genius battle plans resulted in the deaths and enlistment of millions of german workmen because of their brilliant western front tactics of assaulting, while the best course of action (that they eventually came too) should have been to either fortify, of if unable to do so, retreat to more strategic grounds, do some counterattacks from your new positions before they can entrench, maybe even implement salvage and scavenge doctrines taking enemy ammunition, guns and helmets for repurposing for the war effort.