I think the answer lies in the once-popular bumper sticker: QUESTION AUTHORITY
People now put their own judgment ahead of everyone else’s. Sure, they accept authority–but only authority that is leading them where they have been convinced on their own that they want to go! Taken to its logical conclusion, this makes the whole idea of putting one’s faith in revealed truth nonsensical, excepting of course when it comes to the sort of grasp of the truth that the person gains by the “revelation” of direct experience.
When the attitude is, “God, if you have anything to say to me, say it to me directly,” well, that is not an attitude that will have a shepherd. The Catholic faith cannot be twisted in enough directions to suit that attitude. No religion can, unless you count the trivial solution in which each one invents a religion for himself, worshipping a god of his or her own making.
Let us consider the way it was in St. Paul’s day:
*The message of the cross is foolishness to those who are perishing, but to us who are being saved it is the power of God. For it is written: “I will destroy the wisdom of the wise, and the learning of the learned I will set aside.”
Where is the wise one? Where is the scribe? Where is the debater of this age? Has not God made the wisdom of the world foolish? For since in the wisdom of God the world did not come to know God through wisdom, it was the will of God through the foolishness of the proclamation to save those who have faith. For Jews demand signs and Greeks look for wisdom, but we proclaim Christ crucified, a stumbling block to Jews and foolishness to Gentiles, but to those who are called, Jews and Greeks alike, Christ the power of God and the wisdom of God. For the foolishness of God is wiser than human wisdom, and the weakness of God is stronger than human strength.* 1 Cor. 1:18-25
There was a time when a Catholic was a Catholic, and once you were from a Catholic family, there was a limit to how much you could choose to assimilate. Why try to impress someone outside the faith and conform to their ways of thinking, if you’d still be rejected for your pains? If they were going to hang you for being loyal to the Pope whether you were or not, what temptation is there to be disloyal for some gain in the estimation of the world? Aren’t we all now tempted to defend the faith on grounds that the world will find wise or with signs that will impress the world, even though this is a fool’s errand?
The other problem is that a great many Catholics who actually want to know the Apostolic faith well have to go and learn it on their own. They have to come to Catholic Answers or read the catechism on their own or do what they can, because the teaching on the parish level is so often (though not always!) insufficient. There has been a failure to hand on revealed truth with the level of depth and breadth needed by an adult, IOW, and not just a failure of the faithful to accept it. Catholics are really left guessing about which religious writers are orthodox and which aren’t!
This has partly to do with the shortage of priests and religious, because that has necessitated the use of lay catechists who do not have a rigorous background themselves. In that case, catechesis is a matter of the blind leading the blind. My hair has curled at some of the things that I have heard lay catechists teaching. (No, not all of the popes have been canonized. No, there are not going to be women priests some day; Rome has been about as clear as possible about that. Yes, there is a required fast for Catholics before receiving Holy Communion…and so on.) Is it any wonder that the young might a reject a faith in which you hear things from the 2nd grade teacher that don’t agree with the third grade teacher that don’t agree with what Mom and Dad know at home? Giving the youth teaching that has depth and yet is all on the same page is important in order to hope that they’ll continue to accept the faith as adults, too, but not all youth get that, let alone have friends at church who get that, too. Even if your parents teach you, after all, are you not tempted to take an easier way that is being taught to your friends in other families in your parish?