Here is what Cardinal Ratzinger wrote in 1998.
" ... It is good here to recall what Cardinal Newman observed*, that the Church, throughout her history, has never abolished nor forbidden orthodox liturgical forms, which would be quite alien to the Spirit of the Church. An orthodox liturgy, that is to say, one which expresses the true faith, is never a compilation made according to the pragmatic criteria of different ceremonies, handled in a positivist and arbitrary way, one way today and another way tomorrow. The orthodox forms of a rite are living realities, born out of the dialect of love between the Church and her Lord. They are expressions of the life of the Church, in which are distilled the faith, the prayer, and the very life of past generations, and which make incarnate in specific forms both the action of God and the response of man. Such rites can die, if those who have used them in a particular era should disappear, or if the life-situation of those same people should change. The authority of the church had the power to define and limit the use of such rites in different historical situations, but she never just purely and simply forbids them!"
*Can anyone provide a reference to this?
All italics are mine.