This is so central to the decline not only of the oldline churches, but of Evangelicalism and Roman Catholicism in the west:
“These students heard plenty of messages encouraging “social justice,” community involvement, and “being good,” but they seldom saw the relationship between that message, Jesus Christ, and the Bible. Listen to Stephanie, a student at Northwestern: “The connection between Jesus and a person’s life was not clear.” This is an incisive critique. She seems to have intuitively understood that the church does not exist simply to address social ills, but to proclaim the teachings of its founder, Jesus Christ, and their relevance to the world. Since Stephanie did not see that connection, she saw little incentive to stay. We would hear this again.”
I once read an essay, by Peter Berger, I believe, in which he argued that the mainline/oldline had won the cultural battle, in that their inheritors in our society hold to a basically mainline/oldline protestant public ethic, but that they lost the war, in the sense that they (we) were unable to demonstrate that the Church or even Jesus, was necessary to any of it. Why would someone spend their time believing? Practicing faith? etc…

Source: Listening to Young Atheists: Lessons for a Stronger Christianity – The Atlantic