I believe you are making a false distinction between pre-1939 and post-1939 expansionism. Game theory assumes that people rationally evaluate the status quo and their next options. There are plenty of examples to show that this isn't the case in real life, from the Ultimatum Game to the Sunk Cost Fallacy.
If governments were using game theory, 1939 would have been too late to break off. While the Munich Agreement might have resulted in temporary Appeasement, Hitler had clearly shown his intentions to revise the post-WWI order. If he didn't occupy the rest of Europe, Germany was to small to prevail against the rest of Europe. If he occupied the rest of Europe, the United States would be forced to take actions.