Even in the OT, the pattern seems to be that children rarely followed in the faith of their parents, at least until circumstances got bad enough that they called out to God as their last resort. But even then, they’d site the faith and names of their forefathers, not exactly claiming the same faith for themselves. It seems the loss of youth to the world is not just a NT phenomenon, but sin acting in all generations. Youth are taught the doctrines, rites and dogmatics of their faith, but you cannot force them to internalize the faith and make it their own. Only God can make them His own, and our best is to expose them to Him in His Word and the everyday moments of life. It would be nice if it didn’t take some bitter life event for youth to come back around, or perhaps come to Christ for the first time, but sometimes that’s just how God works. The scary thing is that God is not obligated to give them hardships later on by which they might reach out to Him. Some go on in their “success” and never really look back.