I usually don't pull from Protestant articles, and don't necessarily agree with all points from the one that shares titles with this post. However, some things are worth pondering.
I've delved into some factors that have precipitated the Church's decline: Alinskyite influences, Vatican II misinterpretations, gays infiltrating clergy, etc. However, all that being said, don't you still wonder how it is that many Catholics, faced with all this, simply crumpled like a house built of cards, and just went away? It's because they never made the Catholic faith their own. They learned it as children, they observed external obedience.
However, they often resented what they considered to be "the Church's killjoy rules". While they obeyed, they did so with resentment and as those chafing under the reins. They often sought to "push the envelope", to "get away with whatever they could without risking hell". They passed the same lackuster attitudes on to their own children. As long as they were raising "nice" kids who "did't get into trouble", they were pleased. It mattered little to them if their children had as their operative goal in life to attain eternal salvation and to love God and His Church - as long as they were materially successful.
As long as the external societal props and constraints were in place, they practiced their faith externally, as though under constraint. Once the 1960s hit, all bets were off. Religious and clergy left the Church, lay people stopped going to Mass, open dissent became accepted. I don't have to rehearse all the attendant social disasters - including baby murder.
It is for these reasons that I have always looked askance upon a common desire of good people to revert to the society of the 1950s. They fail to understand (or refuse to acknowledge) that at that time, the cultural decline was well underway; it simply wasn't as manifest as it is today.
We, as a Church, need to rediscover the roots for our own lives. In the video below, Michael Voris speaks of "radical" Catholicism. The word "radical" has taken on strange meanings. These days, we think of "radicals" as those who demonstrate in the streets, engage in civil disobedience, etc. That is not correct. The meaning of "radical" is actually "root", or "foundational". We are called to live intensely by the foundational principles of Catholicism.