Perhaps Britain and the USA left Russia to take on the brunt of the German war machine, as you…

From what I have read (not being a linguist, that’s mostly British, Australian and USA viewpoints), there was a lot more pragmatism than anything else, with a background desire for Russia to not advance too far.

The reality of the situation was that Russia had so nearly succumbed. With just a little more focus, a slightly better plan under a general instead of a corporal, or a better understanding of Russian conditions (did nobody on the OKW read of Napoleon?) the Axis could have suceeded, if not in taking Russia then at least getting the eastern third of it. Russia had advantages which were not initially obvious: poor roads, mixed woodland/pasture making living rough possible for tens of thousands of partisans ‘behind the line’ and a very bitter winter. Perhaps only a country under communism could have rapidly moved so much industry east, which was massive advantage, too, as war is firstly about food and then about industrial might.

The British empire and commonwealth forces plus those from the USA could not equal in number those from the USSR on the ground fighting the European Axis forces. The most efficient military way to defeat Germany was with the Russian hammer, so the supplies it needed were prioritized. The other aspect, the political one, meant that the western allies did not want Russia taking too much, correctly fearing it would never release what it once occupied.

As it was, the Russian couter-offences were so successful (I still don’t understand where that quality of general came from) that Germany was on almost constant retreat. Russia ended up with so many well-equipped, experienced divisions in the field that it could have occupied the entire continent, rolling right over the other allied powers if it wanted to.