Our Protestant Churches in the USA are currently suffering from a severe decline in membership. And that decline isn't abating. These churches were the backbone of Christianity teaching, worship services, and family life for a couple of hundred years. Now, it looks like they may not be around much longer, if their decline continues.
The Mainline Protestant church is dying. Church leaders have known this for decades.:
How Mainline Churches Closed Themselves | C. Don Jones (patheos.com)
It's probably pretty complex, but I would guess the main reason for the decline is that going to church is losing it's appeal. I mean, church is supposed to be about stirring each other up to love and good works, and I guess some congregations do that, but it isn't obvious from the outside looking in. What people hear about the church is usually negative publicity. Or maybe they went and they found they had nothing in common with the congregation since there's typically a large age gap between regulars at church and young people. The last thing young people want is to go to church and feel a sense of subordination.
In my experience helping bring many young people to Christ, glory to God, there is no shortage of interest. The typically want something engaging, interactive, and interesting. Being involved in the discussion, able to voice their opinion, ask questions, and get answers rather than being preached at/talked down to for hours every Sunday isn't ideal.
It could also be that God is judging the church for worldliness, greed, corruption, and lies. Only God knows.
It's probably much more complex than this, but that's what I see.