There can be no doubt that St. Pius X's revision of the Roman Breviary, beginning in 1911, was quite drastic, taking steps that changed the very structure and format of the breviary after centuries of unbroken use. At the same time, as Fr. Cekada explains in this very accessible introduction, Pius X was addressing a truly grave situation, where the weekly recitation of the entire Psalter had become more or less impossible, both because of the proliferation of feasts over ferial days, and because of a huge burden of psalmody well-suited for monastics but not for seculars. In other words, Pius X was taking the steps he did in order to restore to full honor a fundamental and traditional principle and to balance it properly with, on the one hand, the veneration due to the saints, and, on the other, the exigencies of pastoral life. The 1962 edition of the Breviary has some weaknesses but is still following the same approach. The 1970 Liturgy of the Hours, in contrast, is a radical departure from the Roman tradition in almost every respect.We plainly have evidence that a "traditional" pontiff took a wrecking ball to the Latin liturgical tradition. However, being that he was "traditional" and must be infallible, we must attempt intellectual acrobatics to find some type of hermeneutical lens with which to codify his actions as Tradition.
Roman ecclesiology leads to a point of cognitive dissonance. It insists upon the affirmation of a human authority with the singular power to arbitrate and legislate and subject to no active correcting mechanism. We find ourselves left with the ultramontanism that provided and continues to the provide the living cultus of recent pontiffs. Otherwise, we're left observing the particular position of Roman traditionalists.
Traditionalists keep bumping up against the same wall, demonstrating that, practically speaking, the history of the papacy since the definition of a particular dogma has demonstrated that such pretensions are untenable. To avoid blatantly rejecting the dogma, the conditions of the dogma, in traditionalist circles, are limited to such precise motions so as to render the whole thing about as credible as magic. They are left then explaining how a number of things they resolutely resist carry no force and are, plainly wrong. Fair enough. But this has practical consequences for ecclesiology. If you can reject a council and the papal interpretation and enforcement of that council, you have stated, practically, that there are limits to jurisdiction and infallibility, that the Roman pontiff is not law unto itself and is indeed subject to criteria to which he can be measured by persons outside of his office. In sum, traditionalists, especially the larger bodies like the SSPX, insist upon a theoretical ecclesiology while practically having developed a Latin ecclesiology more closely related to Orthodox ecclesiology. No sane Orthodox denies the Pope is the Patriarch of Rome (or the West). It is a matter, rather, of this particularly patriarch having assumed powers unto himself that he does not properly have and as a result become dissident. In so far as whatever he says or does or legislates is contrary to the Tradition, he is to be ignored, including his proclamations of juridical and doctrinal power. In so far as what he does, says, or legislates corresponds to the Tradition, he is accorded respect. In all cases, his position as the patriarch of Rome is never denied.
Traditionalists, whether they like it or not, have introduced Orthodox ecclesiology into the Latin Church out of historical necessity. Such ecclesiology is the only way they can justify their existence. They can keep playing a game of cognitive dissonance, but eventually this will no longer be feasible. At some point they have to admit what their ecclesiology really is, drop the ultramontanism, and grow from there.
The Roman Church existed before the Pope. Just ask Paul.