I hope common sense rule the world in the future and we refer to today's religions the same way we refer to greek mithology.
Eventually today's religions will be tomorrows mythologies. However, history shows that new religions will spring up and some of the old and familiar stories will get tied in t othe new beliefs. That is how today's religions came to be.
DNA links Native Americas as coming form teh same group that settled in Tibet. Pre-Buddhist Tibetan religions deal with the same Thunder go as the native America Tribes in the Southwestern United States. It is incredible that a religion coudl survive over 10,000 years being passed down only by word of mouth. My point here, is that it is likely our current religions will last a long time, as they are written down. Interpretations and dogmas will change over time, but don't expect religion to end any time soon.
We can only achieve this by enforcing a complete and absolute separation between state and church. Religion must not be recognized or honored in the government, schools, or public arena. It needs to be practiced in the home and place of worship only, while comparative religions are taught in the schools. It will eventually die out and be relegated to a status of mythology.