[Romulus]

To begin with, it implies that the Mass has always been uniform and static. In fact, the Mass that Juan Diego attended predates the Tridentine reforms by several decades. While substantially the same, before Trent the Holy Sacrifice as offered in the Latin Rite was characterised by a rich variety and elaboration according to location and the traditions of the celebrant's order, most (but not all of which) was pared away at Trent.

[Pyro7480]

To begin with, it implies that the Mass has always been uniform and static. In fact, the Mass that Juan Diego attended predates the Tridentine reforms by several decades. While substantially the same, before Trent the Holy Sacrifice as offered in the Latin Rite was characterised by a rich variety and elaboration according to location and the traditions of the celebrant's order, most (but not all of which) was pared away at Trent.

I'm sure the author doesn't mean that at all. One thing all of the pre-Tridentine Latin "uses" had is the Roman Canon. Also, the bishop of Mexico City at the time was a Franciscan, and the Franciscans are the ones who spread the use of the Roman use which would become the "standardized" Tridentine Mass.