I have spoken with several priests, now in their very old age, who said that they entered the seminaries in the 1950s, well before Vatican II, in order to make the Church more Protestant. Vatican II is a result of earlier changes in thinking, not the start of liturgical changes, and one only has to look at the type of theology taught even between the wars for clarity. Theology was geared already in the 1950s towards ecumenism, the only ideal which many priests and bishops thought would keep Christianity safe from communism and socialism.
I have often told the history of the twelve experimental dioceses in America on liturgical reform, as I grew up in one. I have only met two priests in my life willing to discuss this real concerted effort to change the Vatican's ideas on liturgy by manipulating successful scenarios with course and incremental changes.
My parents, starting before, I repeat, before, and during Vatican II, were part of a diocesan training for the laity. Lay people were divided up into home courses on the history of the liturgy, with built in explanations which would explain changes. Now, I was too young, but babysat my brothers while my parents were part of these classes in peoples 'homes. The parish priest would go to these meetings. Then, the liturgy was changed in light of this build up and feedback was gathered from the laity. All of it would have been positive, as the people were primed for the changes, which were introduced incrementally.
The results of these twelve dioceses were sent back to Rome, which then promulgated the changes. I did not realize until fourteen years later, when I moved to Minneapolis as a young adult, and talked to people there, how unusual my parent's and their fellow diocesan adults' experience were. I began to piece together this occurrence, but it was not until, forty or so years later, I kid you not, that two priests from widely separated dioceses, were willing to spill the beans on this event-the experimental, incremental changes in the liturgy coupled with courses, which created highly successful feedback for Rome.
So, the breakdown of hierarchy started in seminary training before Vatican II and the liturgical changes were likewise planned. Vatican II is a result, not the beginning of the undermining of both hierarchy and liturgy.