Religions and gods exist because people believe in them. When people turn away from religions and gods, they cease to exist! It has happened in history before. Remember Ra, Aten, Horus, Zeus, Apollo, Poseidon, Mithra, Hubal, Tor, Odin, etc, are part of the old memories, nothing more! Many old religions and many old gods had died out.
From my own experience I can say one thing. When I came to Norway about 40 years ago, about 90% Norwegians believed in god and were Christians. But in these 40 years I have seen great changes in this country. Now more than 80% people of this country don't believe in any god and they say they have no religion. This shows that changes are possible.