Poland Stands on the Vistula Line (Hypothetical) - TWiE The First Blitzkrieg

Along the Polish border - 1st September 1939: As the German High Command gauged the risk of launching their attack on Poland, their biggest fear was that the Poles would be able to disengage their Army and retreat intact toward the Vistula River line to reorganize their defense. And, while the Poles may have been criticized for their military incompetence, it is hard to see what else they could have done, except stand and die at the frontier as the Germans had planned. If not, much of the industrial heartland of Poland would have been abandoned, including the Silesian coal fields, not to mention the population centers, where they had planned to mobilize their reserves. *Designer Note: This scenario features historical forces but with the Polish deployment slightly back from the frontier and a defense in depth - would it have made any difference?