For those saying the Soviets could have had trouble in this scenario, the argumentation of Jhon Mosier in the book Deathride seems to make a lot of sense. Mosier belives that the Soviets managed to advance in the way they did, because the opening of new fronts by the Western Allies, diversion of the LW and elite Heer units to the West, Lend-Lease and the bombing campaign. Contrary to the majority of the contemporany historians, Mosier puts the West, not the Soviets, as the decisive factor in Hitler's defeat. While Mosier is a controversial figure by it's interpretations, it seems he credibility in many things, like this article shows about Kursk: Battle of Kursk: Germany's Lost Victory in World War II
I particularly like from Mosier's argumentation, and I belive that if one side needed more of the other, it was the the Soviets from the Western Allies than vice versa, opposite to what is usually belived. The Western Allies had a balanced aerial, naval and ground power to have a more favourable chance defeat Germany alone, or at least very likely defend themselfs (Britain) from it. While the Soviets would be in a more deeper hole by the factors I mentioned, there would also be another factor that would be the absence of the naval blockade of Europe. Germany would have the Western European industry functioning at full steam, while would consequentely meant that shortages of oil and raw materials would not exist by importations. Alternatively, had Germany had to fight the Western Allies alone, she would have to give to the Soviets substantial stuff she would need to fight the Western Allies, which would make it's situation unfavourable.
Quotes from a reference:
The Wages of Destruction: The Making and Breaking of the Nazi Economy, page 420.With hindsight it is hard to avoid the conclusion that after the defeat of France Germany would have done better to adopt a defensive posture, consolidating its position in Western Europe, attacking British positions in the Mediterranean and forcing the British and the Americans to bomb their way onto the Continent. Given that the Red Army ultimately proved to be the nemesis of the Wehrmacht, this is hard to deny. But what is too often ignored in such counterfactual arguments is the grow-ing awareness in Berlin that, even after the occupation of Western Europe, Germany did not have the upper hand in a long war against Britain and America. The chronic shortage of oil, the debility of the European coal mines and the fragility of the food chain, made it seem unlikely that Germany would in fact be able to 'consolidate' its conquests of 1940 without falling into excessive dependence on the Soviet Union. Even if this were possible, the combined manufacturing capacity of Britain and America vastly exceeded the industrial capacity currently under German control and this, in turn, spelled disaster in a protracted air war. The German army, on the other hand, had proved its ability to achieve decisive victory against what were thought to be the strongest armies in Europe. When we bear this range of factors in mind it is easier to appreciate why a defensive strategy seemed like a second-best in the autumn of 1940. After the defeat of France, the dream of a gigantic land empire seemed within reach, and, given the industrial strength looming on the other side of the Atlantic, there was no time to waste.
Page 410.The territories that Germany had conquered in 1940, though they pro-vided substantial booty and a crucial source of labour did not bearcomparison with the abundance provided to Britain by America. The aerial arms race was the distinctive Anglo-American contribution to thewar and it played directly to America's dominance in manufacturing.But though the disparity in aircraft deliveries was extreme it was notuntypical. A similarly vast gulf was also evident in relation to energysupplies, the most basic driver of modern urban and industrial society.Whereas the Anglo-American alliance was energy rich, Germany and itsWestern European Grossraum were starved of food, coal and oil.The disparity with respect to oil was most serious. Between 1940 and1943 the mobility of Germany's army, navy and air force, not to mentionits domestic economy, depended on annual imports of 1.5 million tonsof oil, mainly from Romania. In addition, German synthetic fuel fac-tories, at huge expense, produced a flow of petrol that rose from 4 milliontons in 1940 to a maximum of 6.5 million tons in 1943. Seizing thefuel stocks of France as booty in no way resolved this fundamentaldependency. In fact, the victories of 1940 had the reverse effect. Theyadded a number of heavy oil consumers to Germany's own fuel deficit.From its annual fuel flow of at most 8 million tons, Germany now hadto supply not only its own needs, but those of the rest of Western Europeas well. Before the war, the French economy had consumed at least5.4 million tons per annum, at a per capita rate 60 per cent higher thanGermany's. The effect of the German occupation was to throw Franceback into an era before motorization. From the summer of 1940 Francewas reduced to a mere 8 per cent of its pre-war supply of petrol. In aneconomy adjusted to a high level of oil consumption the effects weredramatic. To give just one example, thousands of litres of milk went towaste in the French countryside every day, because no petrol was avail-able to ensure regular collections. Of more immediate concern to themilitary planners in Berlin were the Italian armed forces, which dependedentirely on fuel diverted from Germany and Romania. By February1941, the Italian navy was threatening to halt its operations in theMediterranean altogether unless Germany supplied at least 250,000tons of fuel. And the problems were by no means confined to the Reich's satellites. Germany itself coped only by dint of extreme economy.In late May 1941, General Adolf von Schell, the man responsible for themotor vehicle industry, seriously suggested that in light of the chronicshortage of oil it would be advisable to carry out a partial 'demotoriz-ation' of the Wehrmacht. It is commonly remarked that the Luftwaffe suffered later in the war because of the inadequate training of its pilots,due in large part to the shortage of air fuel. But in 1941 the petrol shortage was already so severe that the Wehrmacht was licensing itssoldiers to drive heavy trucks with less than 15 kilometres of on-roadexperience, a measure which was blamed for the appalling attrition of motor vehicles during the Russian campaign. Shortages made them-selves felt across the German economy. So tight were fuel rations thatin November 1941 Opel was forced to shut down production at itsBrandenburg plant, Germany's largest truck factory, because it lackedthe petrol necessary to check the fuel pumps of vehicles coming off theassembly line. A special allocation of 104 cubic metres of fuel had to bearranged by the Wehrmacht's economic office so as to ensure that therewere no further interruptions.
The reason I did such comparison with Germany is that I belive that the Soviet Union, while strong militarly, was not so strong as usually claimed it was. This does not necessarily meant the Western Allies would have defeat it easily in this scenario, but it means it would not be so simple for the Soviets do that with the Western Allies, that were comparable in strenght with a fully "active" Nazi Germany, which never existed just by their presence, and was capable of at least bring a stalemate to them.