The US footed a lot of the material costs needed for Europe and the USSR to stay in the fight via lend lease. To the tune of about $575 billion inflation adjusted, and 22% of that going directly to the USSR. https://en.wikipedia.org/wiki/Lend-Lease

So, the USSR played a significant role, but where far less effective than your suggesting.

It is extremely callous to Finland to put it that way!

The USSR attacked Finland while Germany and the USSR were allies against Poland. Understandably, Finland defended itself from this attack and entered into a defensive war with the USSR. Two years later, while this war was still going on, Germany attacked its ally the USSR. Thus Germany and Finland became allies by accident, because they were both fighting the same country. As the Russians started defeating Germany, the Finns expelled the (very few) German troops that they had allowed into their territory, who had to escape to Norway (still occupied by Germany) through the north.

fourstar isn't denying that. Yet the sacrifice of the USSR did not entitle them to hegemony over the free world. Instead it merely saved them and us.

This comment is unrelated to the discussion you are replying to, but I'll give it a brief response. First, all you need to know about whether the Soviet efforts in WW2 and the American efforts in WW2 were better for Europe is to consider the outcomes of East and West Germany. Second, I have serious doubts whether the USSR alone could have prevailed against Germany and Japan. But as to whether the US and the UK could have, you need only ask Oppenheimer.

Key ally how? Beyond diverting troops from the southern front to the finnish theater, how did finland contribute to the german war effort? You also seem to forget that then leader marshall mannerheim refused to advance on key cities in the north, such as st. petersburg and petroskoi even though hitler was quite insistent.