More of why liturgical change. “Armchair strategy of academics,” then-mere-cardinal Ratzinger called it.
It was incomprehensible and pointless to move feast days that people have been celebrating on particular days for hundreds (or thousands) of years, thus totally disrupting the annual nature of the liturgical year. And why change the calendar all around to a three year cycle named as years A, B, or C? Whoever thought that one up?
. . . .
From “the Feast of Faith” By J. Ratzinger ( later Pope Benedict XVI) in 1986:
“One of the weaknesses of the postconciliar liturgical reform can doubtless be traced to the armchair strategy of academics, drawing up things on paper which, in fact, would presuppose years of organic growth. The most blatant example of this is the reform of the Calendar: those responsible simply did not realize how much the various annual feasts had influenced Christian people’s relation to time. In redistributing these established feasts throughout the year according to some historical arithmetic – inconsistently applied at that – they ignored a fundamental law of religious life.”
Of course, Ratzinger later put his authority where his mouth (or pen) was, in 2007 as pope giving carte blanche approval for the Old Mass.