I think a couple of factors could have made a difference. First off is Hitler. Hitler could not except a strategic withdrawl so there are instances when the LW had to divert resources to supply cut off armies. But in my mind that is minor. Adding to what Falcon stated earlier, a strong defeat early in the war may have had the advantage of allowing Germany to react to the Allies, coming up with better doctrine, tactics, technology, etc. before the crunch of depleated supplies could affect them.