That's a reach. Ockham's razor would suggest that a simpler explanation is that westernization leads to decreased religiosity, and that's true for Christianity, as well.
Christian disassociation is a more recent phenomena. There is a higher correlation to the spread of liberal thought and attacks on religion.
There is a direct cause and effect of the disassociation from Christianity. And it is common core and an anti Christian pall over our children. Christianity is forbidden. It is assaulted in public schools now. And this has nothing, no thing, to do with separation of church and state.
Religion is alive and well in school. They haven't quit teaching our children how to write. We are teaching them to read and write in Aramaic instead. We have not removed God from school. We have replaced the God that 70% of this country follows, with the God that less than 1% of this country follow. Our children learn the Allah is the one true God now. They wear burkas, and recite pillars, so stop with the "my tax dollars won't pay for religion in school" bullshit, libs. Your tax dollars are paying for a Saudi Arabia curriculum in American classrooms that has Allah written all over it.