The bit of revisionist history (summarized by Scott McLemee) concerning the decline of mainline denominations in the U.S. that David Hollinger offers will, I suspect, not be overly surprising to those of us who have actually experienced the seemingly chronic inability of many mainline Protestant congregations to communicate across generational gaps, especially as mainline Protestants continue to have fewer children to begin with. The evangelical triumph in the numbers game from the 1960s to the early 21st century, writes Hollinger, was mostly a matter of birthrates coupled with the greater success of the more tightly boundaried, predominantly southern, evangelical communities in acculturating their children into ancestral religious practices. Evangelicals had more children and kept them.
There are few acts more characteristic of Christian hope than the willingness to, when possible, bring children into the world (or adopt those already here) and to raise them in a faith that will form them in virtues that the world increasingly sees as bizarre. And, perhaps paradoxically, few things are more attractive than a church that genuinely hopes.