I think there's a dangerous conclusion to be drawn from the claim that "the mainline churches are shrinking and the traditional ones are growing!"
The traditional ones only seem to be growing because they are having large numbers of children and the culture makes it harder to leave. There's only one church I know that is steadily growing in our communities, and that's the Amish.
I'll share my experience as the chairman of a rural, family-oriented church in the Rust Belt. Before COVID, we had a couple of women (married) my age who were more or less regular attendees with their young children. After COVID, neither came back. This is even though we preach a traditional Gospel without the modern concessions to sin (in fact, we recently left a major mainline denomination over that issue, though in our case it was more related to property rights and avoiding the risk of being closed by the denomination). The church at this point is almost all over age 60.
It's an issue I see in a lot of churches. My previous church was doing fairly well with the younger generation, though even then it was mostly married couples with young children. As someone who was single—and was rejected by the lone single woman in the congregation, who ran away to another church after I tried, though that's another story that need not be shared here—that didn't help much, being surrounded by people who were ahead of me in life but did nothing to help me. (Ironically, that's what self-help tells you to do.) They'd have invite-a-friend weeks, then bring in more married couples with young children like them. I asked around, and they basically looked at me like there was nothing they could do, and I was the problem because I wasn't bringing my own friends. Needless to say, that's how I ended up at my current church, where I am a respected member of the congregation. They can't help me as much, either, but at least they appreciate me.
I just don't see the idea of "hey, if we all just go back to hardcore Reformed theology, lecture everyone on how they'll never measure up to God, and ban women from the pulpit based on a single out-of-context rule Paul put in over his churches" (that there's no evidence that it ever applied to the rest of Christendom and lots of evidence that it did not), "we'll have revival!" panning out. The ones that are "growing" now will see most of those young children eventually deconstruct. It's a bandage on a gushing wound that is our society collapsing, increasingly catering to a narrow, fundamentalist demographic. What works in Moscow, Idaho probably won't be as effective in Little Valley, New York.
But I also believe that this kind of falling away was foretold in the Gospels. We're not going to see the age of Acts in the early church where we're magically going to have thousands joining us.
That said, the church needs to find a way to get those who are falling away. How do we do that? I'm not sure yet. We need to provide aid to those who are in the church, for one. Matthew 7:9-10, Matthew 25:35-45 are key verses here. For singles, matchmaking NEEDS to be a priority. (See Genesis 2:18) That's the biggest crisis I've seen among young people in the church. At ages where their parents were married and had families, single men are struggling to find first dates. I have two friends at one of the larger evangelical churches in my area, and both of them are struggling in this department as well. Why this in particular? Because it's something we will not get in Heaven (Luke 20:35). We're fortunate in America that we don't have many physical needs such as food... but our interpersonal and spiritual needs are at the worst they've likely ever been, and that's the crisis we face that the Church is in position to address.
