I thought this article in NCR was interesting, especially since I lived through the liturgical reforms of Vatican II:
The impetus for liturgical reform and more participation of the laity was already happening well before Vatican II. During the later 1950s, and 1960s, when I attended grade school, the nuns who taught us were already implementing the "Dialogue Mass", in which the students learned and recited the responses said by the servers. The responses were still in Latin, and the students had the English and Latin daily missals to follow. Of course this wouldn't have happened without the consent of the pastor.
There were even places where the priest said Mass facing the people, though I think this was "ex officio" not formally permitted yet.
One thing that was very noticeable with the changes of Vatican II was a greater emphasis on the Scriptures, with the three year cycle which we observe now. Before that, it was a one year cycle, with more repetition of readings, and fewer Old Testament readings.
Of course it was a learning curve, and some people didn't like the changes at first. But it seemed like people got used to it, and the vernacular liturgy was well received. But not everybody was on board, including now some younger people who would have had no memory of the "before times".
From the NCR article: