Well there's going to be a lot of loose ends in this but one thing is for certain, if Germany fails to attack Poland in 1939 it's economy will collapse in 1940.
Put simply the German economy depended on a degree of imports to keep it going, grow the economy ( as Hitler did, mainly through military spending ) and it'll need more resources. This was balanced in part by an expansion of exports but frankly the export end of things never kept up and the German economy steadily ran down it's hard currency reserves. Sooner or later these things come to a head and German invasions weren't that far ahead of their own insolvency, cancel the Polish invasion and that insolvency will catch up and there goes the German economy.
Put simply the German economy depended on a degree of imports to keep it going, grow the economy ( as Hitler did, mainly through military spending ) and it'll need more resources. This was balanced in part by an expansion of exports but frankly the export end of things never kept up and the German economy steadily ran down it's hard currency reserves. Sooner or later these things come to a head and German invasions weren't that far ahead of their own insolvency, cancel the Polish invasion and that insolvency will catch up and there goes the German economy.