There is more than the preservation aspect of church music, according to the council bishops:
The treasure of sacred music is to be preserved and fostered with great care. Choirs must be diligently promoted, especially in cathedral churches; but bishops and other pastors of souls must be at pains to ensure that, whenever the sacred action is to be celebrated with song, the whole body of the faithful may be able to contribute that active participation which is rightly theirs, as laid down in Art. 28 and 30.
There’s a lot of traditionalists fussing over the translation of “participatio,” but I wonder how they would render, “must be at pains.” Article 28 refers to each participant and minister having a role at Mass and performing only that role appropriate to them. So when the people are to sing the entrance chant of hymn, pastors “must take pains” to ensure the choir director and singers do not preempt. When the rubrics of the Eucharistic Prayer say the people are to join with the priest in singing the Sanctus, church leaders “must take pains” not to program a choral piece exclusive of the people in the pews.
Article 30 speaks of the promotion of active participation, defining it as “acclamations, responses, psalmody, antiphons, and songs, as well as by actions, gestures, and bodily attitudes.”
Given the occasional importance of flexibility as an exception to the rule, and not looking to papal participation on one occasion as superceding that rule, the direction seems obvious for parish leaders. Even when it does not suit one’s sensibility or personal choices or tastes, one must give way to the greater good in the liturgy.