Two points.
First, I find it hard to come up with a scenario where the US, UK, and USSR are all fighting against Germany, but there is no assistance at all from the US and UK (even if its just the UK passing on what the US sends them), while something like 90% of the German army is fighting the Russians. To get the leadership of the US and UK so hardline anti-communist that they are willing to cut their own throats like this, its very likely that they are not in a war against Germany in the first place, or their leadership is so clueless that all their other was measures are similarly self-defeating.
You could, just, have the Axis manage to cut the lend lease routes, but that is such an Axis wank that if they can do that, yes, they are probably going to win.
However, to play along, the material sent to the USSR doesn't just disappear into thin air with the loss of lend lease. I think this was covered on one of the "what if the Japanese struck north?" threads. The UK in particularly is much stronger than in IOTL. The Allied effort is much less effective and there is now a chance of the Axis actually prevailing in the USSR, which is bad as that wins the war for them, but at least the US and particularly the UK uses the material elsewhere.
First, I find it hard to come up with a scenario where the US, UK, and USSR are all fighting against Germany, but there is no assistance at all from the US and UK (even if its just the UK passing on what the US sends them), while something like 90% of the German army is fighting the Russians. To get the leadership of the US and UK so hardline anti-communist that they are willing to cut their own throats like this, its very likely that they are not in a war against Germany in the first place, or their leadership is so clueless that all their other was measures are similarly self-defeating.
You could, just, have the Axis manage to cut the lend lease routes, but that is such an Axis wank that if they can do that, yes, they are probably going to win.
However, to play along, the material sent to the USSR doesn't just disappear into thin air with the loss of lend lease. I think this was covered on one of the "what if the Japanese struck north?" threads. The UK in particularly is much stronger than in IOTL. The Allied effort is much less effective and there is now a chance of the Axis actually prevailing in the USSR, which is bad as that wins the war for them, but at least the US and particularly the UK uses the material elsewhere.