Hitler created a lot of little power centers in Germany. For instance, he never fully trusted his senior generals. The SS was pumped-up into a mini-army partly as a counterweight to the Wehrmacht should there be a coup attempt. Hitler loved being the final arbiter of all the political in-fighting that this created.
Yes, but his Generals also never ultimately gave him anything to fear at all, until the very end. German honor, and the German nation, would have been saved by a short and nasty civil war, at the end of which the Wehrmacht would have bested the SS, Hitler would have been gone, and the Final Solution never would have been implemented.
The question is: were the Generals fools who plunged into Russia unprepared winter? Or were they cowards who foresaw a winter disaster coming but were too afraid of Hitler to do anything about it?