A little more history:
Some of these functions, which were more closely connected with the liturgical celebration, slowly came to be considered as a training in preparation for the reception of sacred orders. As a result, the offices of porter, reader, exorcist, and acolyte were called minor orders in the Latin Church in relation to the subdiaconate, diaconate, and priesthood, which were called major orders. Generally, though not everywhere, these minor orders were reserved to those who received them as steps toward the priesthood.
Not everywhere. Makes sense. Certainly duties had to get done, and if a church was rather far from the beaten path, the priest and lay people would take over the liturgical roles. Vatican II offered an opportunity:
Nevertheless, since the minor orders have not always been the same and many functions connected with them, as at present, have also been exercised by the laity, it seems fitting to reexamine this practice and to adapt it to contemporary needs. What is obsolete in these offices will thus be removed and what is useful retained; also anything new that is needed will be introduced and at the same time the requirements for candidates for holy orders will be established.
After reexamination, there is removal, retention: this is one of the main themes of Sacrosanctum Concilium. The pragmatic approach has many advocates. If we had a clear sense of our final goal, this can be a good thing. All this activity just for the sake of reform? Maybe not optimal. What the reformers of minor orders need and needed to know: the goal is the sanctification of the faithful. Not the promotion of people, clergy or lay persons, into offices and role, real or honorary or a pass-through on the way to something bigger.
There is no English translation of this document, but I did find an English rendering here on the Adoremus site.