Not necessarily.If the Germans are depending on supply by rail, then the further they advance, the more difficult their supply would get, because I assume that during a WW1 battle/advance not much would stay intact. So on the gained ground there's no more working railwaysytem. You kinda say that yourself in your quote.
As Zabecki writes, it all depended upon the rail density of the area that they advanced into. The territory that they gained during their Michael and Georgette advances were high in rail, which enabled their advances to be sustained. The subsequent territory gained, however, were low, which precluded the sustainment of protracted offensive operations long-term similarly to Michael and Georgette.
von Papen had virtually no power in the OHL of 1918. For all of Ludendorff's wishful thinking at this point in the war, even he didn't think that von Papen's plans to incite Canadian and American Germans/Irish into insurrection as cowboys or bombing Washington DC with gas blimps was a productive idea at all.I cite as an example von Papen's plan to invade Canada from the USA in 1914 using 600,000 German-American and Irish-Americans recruited from among the US populace, who would go disguised as cowboys.
German Staff plans and reality isn't always a 100% correlation.