Part of the problem is that though people stop attending church you cannot actually leave the Catholic Church.
A few years ago, a chap in the UK petitioned the church to nullify his baptism and allow him to resign, it turned out the Church had no way to do this other than by excommunication.
In the ensuing court battle the RCC was forced to hand over all documentation relating to him "IN THE UK" but could not be compelled to hand over Vatican records of his baptism etc.
As far as the RCC is concerned once they've got you, you are their's for life.
Apparently even Hitler was still a Catholic up to his death, just a very very bad catholic, who did the church a favour by committing suicide which is a Cardinal sin and ensures the perpetrator goes straight to hell, even though Hitler was never excommunicated (Pius the XII repeatedly refused, because he thought a miffed Hitler might bomb the Vatican)