Preachers tell the same stories to adults they told them in Sunday school. There's no growth unless you seek it. At least the megachurches get people off their ass, away from the local jokers, and into a faith-based community rather than a social club. What people do about their weekly serving of baby food once (and if) they decide to grow is up to them. My time in a large Pentecostal Church led me to seek a deeper understanding. My last church had fifty members but it was a college-level study of the Bible. I only left because of proximity, having moved 75 miles away. There's a nationally-known megachurch nearby. Went there a couple times but they were serving baby food. I was far beyond that at that point.