Moscow was saved in 1941 also by intervention of the siberian troops. Had the Japanese attacked the Russia together with Germany in June 1941, those troops had to stay in the Far East, and Zukov haven’t had any reinforcement on Moscow, so Russian had lost one of the positive factor of the battle. There was no need for the Japan to defeat the Siberian troops (and they hardly had defeated Russian, they alredy was defeated in 1939 in Manchuria). It had been sufficient just to keep them occupied, avoiding going as reinforcement to Europe. Having signed a treaty on non aggresion alloved Stalin the freedom to strip all the troops from Far East and bring them in defense of Moscow. Had Moscow fallen, beside of the political and moral effects, Russia had lost their greater rail center, effectively separating north from south rail networks and severing their link with the East. Industry beyond Urals, in fact, used Moscow railway net to deliver their products to Red Army. Lost Moscow, Russian logistic have had very big problems, almost impossible to resolve in few time.
However there is also a German logistical problem to consider. In the plan of Hitler URSS have to fall in 6 weeks. So Hitler do not allow to plan for the winter campaign, because in his view war with Russia have to be finished before. Who touched this argumentation in the OKW was at the risk of being assailed by Hitler with accuse of defeatism. By the way, Winter of 1941 had been the most cold winter of the XX century. Even Siberian troops suffered the cold. Guderian was stoppend more by the frost than from the enemy at Tula, that is at few Km from Moscow. German soldier on the Moscow front entered in battle with the summer uniform. Rifle and MG have not lubricant oil adapt to the lower temperature. Even Panzer may stay always with engine on to avoid freezing problems.
Not to re-open a discussion, but there is a big difference between Waffen SS and SS. The former was essentially Wehrmacht crack soldiers. The latter are originally a private militia of Nazi Party, that first became an internal policy force and then was appointed to manage affairs in the occupied teritories of Europe. Their “management” was cause of a lot of atrocities, murdering, deportation and plundering. They were also involved in the genocide of Jews.
Waffen SS were wonderful soldiers, among the best in WWII. Maybe only veteran Marines and hardened Guard Red Army Soldier may compare with them. There are some episodes of they being involved in atrocities, this is true. Particularly where there was not the possibility for the ordinary SS to intervene. But also soldiers of other nations make the same thing.
For example, in a recent book I read I was orrified by the story of what Russian soldiers made in Germany and specifically in Berlin, in 1945.