It was a wildly different situation. The Allies were not the winning side in June 1941 when the Germans launched the invasion of the USSR. France had fallen and Germany&its allies and puppets had control of the entire European continent. No way Hitler would have opened a second front had France stalled the Nazi invasion with the battle still fiercely taking place.

If we compare WW2 to the current era then its like Poland manhandling Nazi Germany, who has lost all its initial invasion force. With the Allies staying out of the war but cheering and sending weapons. Madness for the Germans to also try their luck on the French&British at that point when even getting to Warsaw is impossible.