Comment 2 by Jay G

"The report said researchers found belief in God is higher among older people regardless of where they live."

There's a shocker. Some people start to believe in God as they get older and can see the "end".

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:

A new scientific truth does not triumph by convincing its opponents and making them see the light, but rather because its opponents eventually die, and a new generation grows up that is familiar with it.

I think there was an episode on Mythbusters in which they busted the adage "you can't teach old dogs new tricks", though they admitted that it took longer to teach old dogs than young dogs. The neurological mechanism behind it is most likely similar to the one found in humans, since habits of thought become entrenched. The longer they're indulged, the more neural connections are forged and reinforced, and the more effort is required to shake them up.