Something important to consider is that you are looking at the continuation of Judaism after the fact. If you were to go back 2,000 years, and try to predict in advance what would happen, it would be reasonable to expect that a society of some sort would survive, though predicting exactly which society of the many available would probably be beyond you.
So yes, Judaism survived against all odds, but the survival of any one particular society would be against all odds. A world without God would likely have some society, and which particular society would be ...
You probably won't see this since it's six years old, but just in case, why do you think such a long time? A significant portion of people who are in the AI field give a much closer number, and while predicting the future isn't exact, 500 years is a pretty big difference from the numbers I've most often seen.