Why was the Germans only lead by Hitler?
Hitler had various levels of government in place to dictate what people under his rule did. He had men to control radio communications and newspapers (Propaganda Minister Joseph Goebbels), men to look after the Reich's finances (Minister of Economics, Walther Funk), and several men to look after the various branches of the military (Hermann Goering lead the Luftwaffe [airforce], Karl Donitz lead the Kriegsmarine [navy], and Wilhelm Kaltenbrunner looked after the OKW [oberkommando der wehrmacht, the armed forces]).
I guess my point is that not just one man maintained control of Germany during WW2. Hitler was intelligent enough to realize he couldn't do it all himself.