Composer David Haas wrote the following in 2002:

“Acclamations … help empower and form the assembly as co-celebrants in the liturgy.”

Father Edward Foley wrote in 1998:

“The associate formerly said Mass, but now this redefined parochial vicar and member of the Parish Ministry Staff presides at the eucharist at which the assembly is the principal celebrant.”

Composer Marty Haugen wrote in 1984:

“With the advent of post-Vatican II liturgies, the assembly was given a new mandate and opportunity — to rediscover and express its integral importance as the primary minister of the Sunday eucharistic experience.”

Father Eugene Walsh, a seminary professor in Baltimore and principal author of The Place of Music in Eucharistic Celebrations, wrote in the 1970s:

“The entire parish assembly, therefore, is celebrant of the eucharist. The presider is simply the leader of the assembly. As leader, his task is to engage the assembly in the eucharistic prayer.”

Whence cometh such theological notions?

A good place to search might be this stupefying tome of PDF documents:

      * *  NPM Magazine Archive — (1970s and more)

It would take several decades to quote and explain those articles, so I won’t try. However, here’s a fairly good “sample” of what’s there:

      * *  “First, the Assembly Gathers” — Article by Fr. Eugene Walsh (1982)

Reading that article, you’ll find quotes like:

The most important thing that people can do at a parish Sunday Mass is to take the trouble to gather with each other.   [ … ]   The parish assembly is the first and primary minister of the parish Sunday Mass.   [ … ]   The full, life-giving sacramental sign of eucharist is the parish assembly.

Dull and feeble and half-hearted sacraments are not life-giving. In fact there comes a point where they begin to be death-dealing.

The first task of all specially designated ministers [i.e. priests and deacons] is to serve the assembly. Their conscious and deliberate target is to help the assembly bring itself to life …

Feel free to let me know your reactions to that article by Fr. Eugene Walsh. I found it shocking … and quickly phoned my spiritual advisor for counseling!   (Not kidding.)