Let's just imagine that nuclear war happens and wipes out everything and small human communities emerge after many years of hiding and they have to rebuild and relearn everything, but there are no signs of old world's religions. What would of happen to the people in the future, would they create a new religion, or would they become more scientific. I would imagine they would become the same as we are today, some are religious, some are not.
2000 years from now..
Science will always be the same, the same laws of physics will be there, the same hydrogen and oxygen atoms, math and chemistry will be the same. You can't change the laws of physics, they are constant and unchangeable, over the years those futuristic people would discover what we did.
Religions, however, will be something brand new made up again if old scripture would get erased. So there are no old books available and people from future can only find artifacts of small blue people.
It would be very easy to imagine that the people from the future in their early years would create a brand new Smurf religion, and Papa Smurf would be a futuristic version of Jesus, Muhamed, Shiva, or whatever superstition you are worshiping in today's society. Gargamel would be a brand new Satan, and cats would be considered as hell hounds. That depiction of my vision would be extremely violent towards cats (see what I did there). Poor critters would be erased in a matter of years.
Religions can help some to find their peace and that's cool, but when religions get violent and impose their beliefs and indoctrinate from the young age, specially when you know it is all made up, an invention if you will (like the future blue man religion in my story), why would anyone rational be a member of such a community today?