Well, one of the reasons for this moral decay, IMHO, is that the Church after Vatican II completely abandoned its responsibility to teach and preach the truth.
We wouldn’t have such a low birthrate had Vatican II, with its implicit rejection of the traditional teaching authority of the Church, not given people the feeling that it was ok to reject Humanae Vitae. There are many things that would not have happened - the hugely high divorce rate, for example - had the Church stuck with its mission and not gone off into wishy-washy leftwing political activity and warmed over Freudianism.
But Francis talks about the “enormous fruits” of Vatican II. He clearly sees nothing wrong with it at all.
I have a lot of problems with Vatican 2 (the destruction of the beauty of the church) but I don’t think the Catholic Church is responsible for world wide promiscuity, corruption and moral decay, lol. The pill, Hollywood, bad educational system, radical feminism, divorce,gay rights all had a hand in our destruction.