I'm really tired of the trope that the great falling away from the faith has been because the Church has made the observance of the faith "too easy." "My yoke is easy, and my burden light" has been a selling point for Christianity since its inception.
I don't have the whole answer to the question of what St. John Paul II called the "silent apostasy," but here's what I think is one possibility:
The Church, and religion in general, has been in decline, not since Vatican II but since the Enlightenment. In fact, I would be tempted to argue that, without Vatican II, the decline after World War II would have been even more catastrophic. I think it may well have been the "loosening" following Vatican II that kept the Church supple, and prevented it from becoming brittle and shattering.
Rather, I think what could have been a major factor in the silent apostasy was that we no longer see ourselves to be in need of God.
All of the approved apparitions since the Enlightenment have had two great themes: repentance and mercy. The Blessed Mother has continually pleaded for people to turn back to God (i.e., "repent") and our Lord has promised that infinite mercy awaits those who do so.
But when we see no need for God, we have no one to return to and see no need for mercy. What follows from that is apostasy on the one hand and unfathomable brutality on the other—because when you have no need for mercy for yourself, you have no desire to extend it to anyone else.
Perhaps now the constant call for mercy from the popes of the 20th and 21st centuries finally makes sense. What will restore the faith is not a more stringent observance of it by the "elite," "hard identity" Catholics, but repentance for our own faults and mercy for the faults and weaknesses of others.
(Image: Divine Mercy medal, Pixabay.)
