I have lived through the last fifty years of turmoil and change in the Church, but I cannot accept all the blame for what has happened during that time. But before I offer a few thoughts on what happened, please bear with me whilst I digress.
My family lived in the parish of Corpus Christi, Gateshead. Before the church was built, Mass was celebrated in the school hall, and at that time the parish was called the Blessed Sacrament parish. However, when the Protestants made fun of the name, it was changed to Corpus Christi and that put an end to the derision because the Protestants did not understand the Latin. So I was told. The building of the church almost led to a disaster -- it was built in the early thirties by the lads of the parish (to give them jobs during the Depression), but when the walls had reached a goodly height, the whole thing collapsed one night. No-one was hurt, but after that a proper builder was brought in to finish the job. The first parish priest I can remember was Canon Henry Parker, who was pretty strict on his curates and if anyone dared to cough during Mass he would turn around from the altar and glare at that person until they blushed with shame -- you can imagine, when he was saying Mass the church was very quiet! But one other thing I remember him for in particular is that Sunday after Sunday he droned on about the questions of the Catechism: my Dad, brother and I were able to catch up on our sleep and my mother's elbow was a bit sore from poking my Dad in the ribs to stop his snores being too loud! However, the net result of this is that as a congregation we were fairly well clued up about our Faith. And of course we children had our regular Catechism class in school each day, with an annual verbal examination by a priest appointed by the diocese to check on our knowledge of the truths of the Faith.
As a young priest I can remember the diocese bringing out a course of instructions based on the Catechism to be given during Mass on Sundays; Father Aidan Pickering, who taught me General Science at Ushaw College, produced one such course. Consequently, Mass-going parishioners had a chance to be reminded of their Faith.
Some time in the '60s or '70s, the Catechism was dropped from our schools and courses of instruction during Mass were dropped in favour of homilies (What is a homily anyway and why is it different from a sermon?). I myself have been reprimanded in recent years for giving a course of instructions based on the Creed. My impression now is that many Catholics are not too sure of what to believe. So the Faith that they do believe becomes ever more tenuous and it looks as though some Catholics 'cherry-pick' bits of the Faith which they like and throw out other bits which they don't like. This leads to a general loosening of the Faith and to a vague feeling that maybe there is no difference between any Christian group, and since we are all without exception going to Heaven why bother?
Another thing. In the '60s we had Hippies, Flower Power, "California Dreamin'"; we had Roy Jenkins, the British Home Secretary, bringing in laws on homosexuality; we had the Abortion Act. And we had the debate about Contraception. When it was learnt that Pope Paul VI was considering ruling on this subject, the mood music in many Catholic journals, and even, I think, in the secular press, and the rumours apparently coming from Rome, all indicated that the Pope would come down in favour of contraception. When Humanae Vitae was published in 1968, the sense of shock and disbelief and disobedience around the world was enormous; many individual priests, parish groups, national conferences of bishops, refused to accept the word of the Pope. Some people left the Church, but many others were left with the feeling that they now could make up their own minds about this (and perhaps about anything else as well). National Churches were also affected and became more nationalistic. Obedience had been a very strong feature of clerical and lay life; from the '70s onwards obedience waned.
There is one thing which I think is on the whole better these days. In the '60s, I cannot remember that the English Church projected its strength on the political scene; the Abortion Act and other liberalising factors were lost by default. Nowadays there is a strong pro-life movement attempting to use the still considerable strength of the Catholic Church to uphold true Christian attitudes in social life.
I am not a sociologist and this is not meant to be an in-depth explanation of Why It All Happened. Perhaps others would like to add their comments to flesh out this picture
I know this all sounds doomy and gloomy, but really I am an optimist and there are good things happening in the Church today (one of which I hope to post about soon) and we need never despair. This is God's Church -- we need to work hard and then leave it all in His hands!