AND/OR it's simply that old people are the last remnants of a time when religion was widespread, but since a series of liberation movements over the last few decades has weakened old traditions, the younger generation grows up in a more irreligious world. A.K.A. the Max Planck effect:

I doubt it is as simple as that. As long as the idea of a god is present at an early age, many people will probably fall back on that idea/belief when they truly realize their own mortality. In a slightly more adult fashion of course. I think this "idea" of a god lingers on in your subconsciousness, unless you've given it a good deal of thought and reached a conclusion by yourself for yourself. Many people don't, until reality shows itself and you start to age with your experiences.

In short: As long as we talk about gods and read about gods, there will be faith. After all, we can't proove no one is there. At least not yet. :-)