Lack of Perseverance
It seems to me that most children attend church because they are simply following their parents’ example or direction. This practice may lead them to habitual attendance even when their parents are absent.
However, we live in a culture that increasingly emphasizes utilitarian relationships, discouraging even meaningful actions unless there is some compensating reward. So too in religion, if someone is not experiencing the immediate reward of attending church, then they may be inclined to leave.
The reality is that authentic worship “rewards” us with a profound encounter with God, but it is a gradual process. If a person does not persevere beyond their young adulthood, they may never truly discover that encounter. Yet, when they do, nothing will hold them back from the liturgy. And as the mystics say, nothing delights God as much as when we seek Him not for rewards but simply for loving communion.