What if after the French surrender the Germans said "Ok we're done. All we wanted to do was solve the Polish situation". The surrender document has France recognizing the German takeover of Poland, but otherwise returning France to the same position it was in 1939. Germany does the same with Norway, Belgium, The Netherlands, Denmark and Luxemburg.
What does England do? While the government can continue I think the general population will start questioning why the war would continue.
If Germany has 3 to 4 years to consolidate their gains in Austria, Czech and Poland what kind of shape would they be in by 1943-44?