If I was playing as hitler I would have held out another 10 years, built the manhattan project, bought all the world's uranium and built as many nukes as possible then forced a nuclear non-proliferation treaty through the world congress so nobody else could build them. I do this in almost every game I play and you end up with the rest of the world scared shitless of you and giving you whatever you want for the next 200-300 years. In my current game I took over 2/3 of the world without ever firing a shot.