Whoever won would have been much weakened. The reason Hitler started WW2 was that his system was a complete bust economically -- he HAD to conquer and loot other countries to keep afloat. Stalin was in much the same boat. We would have been better off supplying Britain while Germany was occupied elsewhere.
The Nazis were focused on France first, then the UK and then the Soviets.
There would have been no UK left to supply if we had waited for them to turn their attentions elsewhere.