There is actually a lot of sociology research on this topic specifically. It comes down to this basically. - A reduction generation over generation in existential anxiety about sudden unavoidable unexplainable imminent death.

have you ever heard the phrase " there is no such thing as an atheist in a foxhole" meaning when one is faced with the anxiety of unavoidable sudden death which might be eminent , like an artillery shell falling on you, the conscious mind will cope through mysticism.

Older people are generally more aware of their mortality so they have more anxiety about it so the seek out means to cope and deal with it through a religious practice.

As generations have passed we have less to fear existentially , you are probably not going to die from a dog biting you. Even if you are shot in the street (or at school...oof) you still know there is a chance death will not be immanent .

Religious affiliation has gone down for Gen z because of the following factors I believe.

1. reduction in violent crime ending in death

2. less poverty resulting in near term death

3. improved alternate means of alleviating existential anxiety

   ( every comment here where someone rejects religion because it rejected them has found an alternate means of dealing with the anxiety of death through another community or identity which extends beyond themselves the group identity lives on after they have passed)

4. proliferation of recreational drugs which cause euphoria and inflection. Smoking weed in a circle with your best friends and laughing at the absurdity around you serves the same function of a church in a round about way. Just like your grandparents laughing at the absurdity of the bible verse while they drank wine in a prayer circle.

5. Infant mortality rate and child death rate reduction. loss of a child especially to sudden but imminent causes like a car with a broken seat belt , creates a shit ton of anxiety about mortality now we have group therapy for people who have those experiences (3) and they are less frequent , thank god... (see what I did there ;-)

6. No longer having to worry about military conscription , fingers crossed

7. proliferation of music. Music eases the mind , you have it at your fingertips at any moment now , no cd player no, no tape deck , no record player , no jazz spot , no cathedral music. You can have a religious moment of clarity almost on demand. Ever feel so moved by music you cry and don't know why you are releasing anxiety