If you believe the evolutionist's dating methods, they now have man pegged at 160,000 years. But I don't think so. Based on the assumption that the Bible records a full history in Genesis, skips no generations and that the ages of Adam and his descendants are accurate. I think it's only been about 6000 years.
But the first 2000 years are a pretty good argument for the existance of atheists. At least mankind was in pretty deep denial. Here's how the Bible says they survived....
Gen 6:5 And God saw that the wickedness of man was great in the earth, and that every imagination of the thoughts of his heart was only evil continually. 6 And it repented the LORD that he had made man on the earth, and it grieved him at his heart. 7 And the LORD said, I will destroy man whom I have created from the face of the earth; both man, and beast, and the creeping thing, and the fowls of the air; for it repenteth me that I have made them. 8 But Noah found grace in the eyes of the LORD....11 The earth also was corrupt before God, and the earth was filled with violence. 12 And God looked upon the earth, and, behold, it was corrupt; for all flesh had corrupted his way upon the earth.
Fortunately God is not going to destroy us all again, until He destroys the Earth completely. However note despite Noah, man hasn't changed.
Gen 11: 21 And the LORD smelled a sweet savour; and the LORD said in his heart, I will not again curse the ground any more for man's sake; for the imagination of man's heart is evil from his youth; neither will I again smite any more every thing living, as I have done. 22 While the earth remaineth, seedtime and harvest, and cold and heat, and summer and winter, and day and night shall not cease.
"Judeo-Christian ethics do not predate the human community, and yet it managed to cross the finish line without annihilation...hmmm, which we may yet reverse in our morally advanced society."
Managed to cross the finish line without annihilation? Except for Noah, man wouldn't have.