Thanks a million for mentioning the "Room" movie. I haven't seen it and hoped that someone who had would jump in to help others reading this.

What you said confirms what I kept thinking while writing this: "Bet religious motifs have ZERO chance of making into the film." And the Seventies sounds about right for when that "kids are resilient" cliche took hold, because I believe that was when you also started seeing divorce movies like "Kramer vs. Kramer" that would have divorce lawyers saying that to comfort parents (and moviegoers).