Perhaps part of what is going on may involve two trends: First, the desire of teens - and the 20-30 somethings as well to remake Jesus in their own image - in the image of their values, priorities, education and world-view; Secondly, the rising influence of atheism being pushed not only by the current spate of tomes on the subject, but by their education in the hard sciences, especially Biology with the current version of "blind chance random mutation" evolution with any Divine influence on the process rigorously prohibited.
Along those lines, in my area there are a lot of well educated, affluent professionals who are making a point of raising their children with
no exposure to religion in
any way, shape, or form. Further, many of those parents have moved from a contentious form of atheism to one which is characterized by complete indifference to religion and spirituality, whether theistic or not, and whether it is organized or not. Personally, they refuse to even discuss the subject hypothetically. For them it is all myth. It is not worth arguing about or even considering. Case closed. Move on.
How do we cathetecize those people and the teens coming from those families? That seems to call for a determined missionary effort which starts with such ultra basics as proving that God exists. It is going to be (it is already) hard to reach teens who have those kinds of parents. It is going to be hard to do that if the missionary says in effect: "Here is the Bible. Of course we don't really believe it is
really true as written. The history and science are wrong. The History is heavily edited, much if not most of it is not supported by archeology: and the text is heavily redacted - "the books cooked." The science is, well, pre-scientific. The psychology especially concerning sexuality for instance, is hopelessly out-dated. But there are things of value in that Bible . . . somewhere . . . maybe . . .?? So lets study it . . ."

One basic principle of marketing is that the salesman, in order to be really effective must really, enthusiastically
believe in what he or she is selling. This is a problem for a missionary who is theologically and socially liberal and has broad doubts about the faith (like the PECUSA priest who told Gene Robinson - then a college student - to just not say the elements of the Nicene Creed which he did not believe.) That hardly builds confidence in a faith-system. Would a rational person be willing to become a martyr for that kind of "faith? Other people are not convinced with this sort of thing: "Church is such marvelous theater. . . we should not deprive ourselves of it just we do not believe a word of it." Now, someone will grouse taht an evangelist is not a salsman; that he or she is not involved in marketing. But that is arguably splitting hairs. The basic principles apply.
Granted that there are and have been two systematic theologies, two hermeneutics being taught in the mainline Church for a very long time, and they have coexisted comfortably. Until now. Granted, my concern is colored by the fact that I am a social and theological conservative who lives in a part of town in which virtually everyone is college educated and many have advanced degrees. All my close friends are college graduates, most have advanced degrees, and they and I are all charter members of the "wine and cheese and chamber music at an art gallery" set. Things are no doubt different in other parts of town, and among other people than those I usually hang out with. But there are times when it feels like religiously and spiritually, Europe's present is our future unless we do something about it now. Those teens are our future.
