The increase in young people drifting away from the church occurs over the same that large numbers of them started to go away to go to college.
Well, a lot of changes also coincide with those two things, so I'm not arguing a cause-and-effect. However, I am advocating that we contemplate whether there is a cause-and-effect, rolling that around in our minds. I am not referring so much to young people fleeing the church at those ages because of what they teach at colleges. That's all very interesting, of course, but lots of people analyze that. I'm thinking of the simple drifting out of the community. They go to far places - anywhere beyond 20 miles if far enough to split them from their congregation. Their last years in the congregation were often heavily-bonded with their own age group, so if they return over vacation, even the people that they know they do not know. After graduation this only intensifies.
Community is very near the heart of the gospel, but it is greatly weakened in America. It is true that immigrants tended to seek communities with others of their own group, as in Lake Wobegon's German Catholics and Norwegian Lutherans. Yet that quaint and fictitious community is the experience of nearly all Christians outside America, except in cities at ports and crossroads. America had its movement and its frontiers, so our theology came to focus more on decisions and conversions to the broader Church. That had good consequences in terms of Americans recognising some value in the practices of other Christians and gradually learning some tolerance. But the de-emphasis on community meant we never batted an eyelash when my generation all started to travel way to go to school, never to return to their home congregation and thus less likely to join some new congregation where they eventually settled.
Plenty did join new churches, certainly, but it's abundantly clear the numbers were down. Some of that was intentional, but a lot of it was just drift, of young Christians who mean to go to church or hope to or plan to, but are in a place where they have no connection and they have to come in cold. Often, if their spouse is also a believer they were not a believer in quite the same way, so that's an additional hurdle. One has to be determined to keep the connection going, because the discomforts are stacked against you and the comforts will not come for months or years.
It has been two generations, now starting a third, of young people going far and not having a faith community there. What were we thinking? Now even those who stay nearby consider it normal to leave off attending church, as their friends aren't there.
I write this as one who intentionally went far away to school and considered separation at 18 entirely normal and preferable, and sent all my sons to far places when they finished highschool. So I am assuredly not criticising anyone here. Unintended consequence of how we designed our education system in terms of the importance of careers. Perhaps not the best trade-off.