Talk about gambling!
I agree that the early bloodless victories and the wins in Poland and the west would not have been won minus Hitler's rather mad gambles. The professional military would not have risked war with France and England over Poland even. Part of that was the low level of ammunition reserves. As of October 7 1939, the Germans had enough bombs for 14 more days of fighting. Other ammunition wasn't much better--enough for less than a month more of fighting. I haven't seen exact figures, but I'm guessing the spare parts situation wasn't much better, and a very high percentage of the trucks the Germans used in Poland were temporarily unusable by the end of the conflict.
There were good reasons the Germans waited seven and a half months after the Poland campaign before they attacked in the west, and gave logistics like ammo priority during that time. The severe winter weather was part of the delay, and the Germans did a lot of retraining to take care of deficiencies they discovered in Poland, but a lot of it was building up the ammo stockpiles they should have had before they started the war.