Here’s a quote:
In his seminal work The Spirit of the Liturgy, then–Cardinal Ratzinger argued that the purpose of liturgy is not primarily to develop human relationships, be creative in worship, or promote humanitarian agendas. Rather, the liturgy is the worship of God. The forms and styles are given to us by the Church of the ages; similarly, bishops and clergy are not innovators but stewards of the inheritance they have been given.
Read the whole thing on insidecatholic.com. I’ve got to quote some more from Father Dwight Longenecker’s excellent article (hat tip to Toni for sending me the link):
Similar reasoning explains Benedict’s wish for Gregorian chant and sacred polyphony to be used more widely. No one expects that every parish will suddenly switch to Gregorian chant and polyphony but rather that a wider use of traditional music will influence the positive development of Catholic sacred music.