General Gotthard Heinrici, the commander of the Germans Fourth Army's XXXXIII Army Corps at Moscow and by war's end, the Wehrmacht's premier defensive specialist, congently assessed the reasons for the Germans failure.
Hitler's meddling in military affairs was not on the list of the top 7 reasons.
Politically, Hitler underestimated the inner stability of the Bolshevik system was his first reason. Followed by, Militarily, the Russian armed forces were suprisingly capable.