Armageddon has happened many, many times in human history. The fall of Rome and the collapse of the Mayan civilization are but a few examples. When ever Armageddon comes, there are always survivors. Even in a full scale nuclear war between the United States and the Soviet Union; it would be a nuclear Armageddon for both countries; but there would be survivors that would start over.
Besides the fact that in about 500MY to 1000MY, due to solar evolution, Earth will be a green house world like Venus and the fact that the human species has only been around for 150,000 years and it unlikely to be around 5 billion years from now when the your sun goes red giant.