Charlie Steiner
Footballguy
I see this as well where I live, combined with an age/generational shift. The non-denominational churches are filled with young parents with small children. At least here among the people I've talked to, the reasoning is simple. The ND community is much more casual, come and go as you please, wear what you like, no strict kneeling/standing/sitting/reciting, let's Love Thy Neighbor a little more and fire and brimstone a little less.
I get it. I grew up attending Catholic mass every Sunday morning at 0830, and attended Catholic school from 7th-12th grade. Once I got "of age" and my attendance slacked I started getting comments in the grocery store like "I haven't seen you at church in a while". I don't need the structure of a mass in order to be religious, and I agree with the Amy character on Big Bang Theory: "I don't object to the concept of a deity, but I'm baffled by the notion of one that takes attendance." .
I think what's getting lost in the sauce is the focus on what one does vs why one does it.
In the early days of the church, people went because they wanted to go, because they were committed to the truth they heard and it was the guiding force of their lives, not because there's any line in scripture that says 'thou shalt meet at church every Sunday lest ye not go to heaven'.
I grew up in the Lutheran church, but by the time I was in high school, I stopped going, and by the time I was in college, I was 'done' with the church and pretty pissed at God. When I was 30, I was at a point where I turned back to God, was 'born again' and started reading the Bible more and going to church because I wanted to worship with other believers. After a few months, I went back to a Lutheran church and was stunned by how much of the service was taken directly from scripture, which is where I think churches start to go off the rails. They take for granted that what they do is supposed to or does have scriptural underpinnings and the true meaning of why they exist is lost in the weeds, because the focus has shifted to doing X,Y and Z to be 'right', instead of understanding why doing X,Y and Z is part of one's relationship with 'the divine'.
God doesn't take attendance; religious leaders focused on the religion instead of the deity do.