If you read the history of the time, the Lefty termites were already undermining the Church structure and had been for decades. VII only gave them cover.
I came across evidence of that a few years ago, in the choir loft of an old church. The hymn books from the late 50s gave hints, in terms of “modern” illustrations and the way things were expressed in the foreward and such, like Vatican II was coming.
In other words Vatican II was a formalization of leftist error.