Religious media has always had an audience, and has been successful. It's only natural that it's more popular now than previously simply due to natural market increases (more Christians, digital media, cheaper access to high quality film production, etc). The idea that a Christian film grossing $40 million proves morality is on a rebound strikes me as ridiculous. Like Tyler Perry films, Christian films have a specific loyal audience that helps make them a success. Throw in people suckered in by the "inspirational" angle and you have a low budget high return hit film.
My grandma used to live in a retirement home run by one of the largest mega churches in Detroit. They'd bus many of them to the movie theater to see each of Tyler Perry's films. Or they'd buy rights to show the film at the church. I know white churches do the same for films like God Is Not dead and Son of God.