Remember, this “newer” introduction to this GIRM edition was released eleven years ago. In today’s brief section, the modern Roman Rite is compared favorably to the Tridentine Missal:
6. When it set out its instructions for the renewal of the Order of Mass, the Second Vatican Council, using, namely, the same words as did St. Pius V in the Apostolic Constitution Quo primum, by which the Missal of Trent was promulgated in 1570, also ordered, among other things, that a number of rites be restored “to the original norm of the holy Fathers.” From the fact that the same words are used, it can be noted how the two Roman Missals, although four centuries have intervened, embrace one and the same tradition. Furthermore, if the inner elements of this tradition are reflected upon, it is also understood how outstandingly and felicitously the older Roman Missal is brought to fulfillment in the later one.
 Second Ecumenical Council of the Vatican, Constitution on the Sacred Liturgy, Sacrosanctum Concilium, no. 50
Two adjectives over which Catholic traditionalists (and maybe a few others) would puzzle: outstandingly and felicitously. If that original norm was so worthy, why did we stray from it, or indeed, why was it updated through the centuries? For different Catholics, I imagine the answer is different. Some indeed take comfort in the experience of an outward continuity. And others see a bit deeper into things. Perhaps there is the perception that people of the first or fourth centuries were closer along the path of holiness than we are today.
A better standard than continuity would be striving for deeper holiness, for calling upon God’s grace. In the countless centuries of Christianity to come, who is to say that believers of the twentieth millennium won’t look back on believers of the third with some high regard? And if we don’t aim for such, why not?