Likewise urge the young men to be sensible; in all things show yourself to be an example of good deeds, with purity in doctrine, dignified, sound in speech which is beyond reproach, so that the opponent will be put to shame, having nothing bad to say about us. Titus 2:3-8 (Emphasis mine)
What I've seen over the 20 years of being a Christian is young people graduate high school or college who leave youth group/student ministry and follow their peers to younger churches.
Those younger and hip churches lack older saints who have a gold mine of life time wisdom who are not connecting with these younger men and women. This gap creates an environment of immature baby Christians, who learn from more immature Christians, and they remain immature Christians.
Over time this problem creates an imbalance of age groups in biblical churches.
So why is this happening?
Age segregation defies the Titus 2 main principle of discipleship. The passage above is singular in context of a one on one relationship.
If we separate young people in to their own culture within the church they'll have a hard time connecting and bonding with older men and women in the church's main population.
Often times the young person of an unbelieving family are sent to a youth group with their friends, but they are not getting one on one from a mature Christian. They often slip through the cracks and go on unchallenged in their Christian walk.
Even though I disagree with Mike Hauser's pragmatic philosophy of WHY young people are leaving the church they grew up in, I do agree with his solution because it lines up more to the biblical standard.
Reflection on Becoming a Titus 2 Woman by Sherry Wilson
Pyromanics: "Too many old people"?