"Chiudo gli occhi, e mentre le labbra mormorano le parole del breviario che conosco a memoria, io abbandono il loro significato letterale, per sentirmi nella landa sterminata per dove passa la Chiesa pellegrina e militante, in cammino verso la patria promessa. Respiro con la Chiesa nella stessa sua luce, di giorno, nelle sue stesse tenebre, di notte; scorgo da ogni parte le schiere del male che l'insidiano o l'assaltano; mi trovo in mezzo alle sue battaglie e alle sue vittorie, alle sue preghiere d'angoscia e ai suoi canti trionfali, all'oppressione dei prigionieri, ai gemiti dei moribondi, alle esultanze degli eserciti e dei capitani vittoriosi. Mi trovo in mezzo: ma non come spettatore passivo, bensì come attore la cui vigilanza, destrezza, forza e coraggio possono avere un peso decisivo sulle sorti della lotta tra il bene e il male e sui destini eterni dei singoli e della moltitudine.”I am not entirely confident about framing this as a "commentary" on the effect of praying the office itself. In all truth, without factoring in his biographical context nor the literary context, the Breviary is more the McGuffin - life in the Church is more the plot point.
Anytime a figure from the liturgical movement is mentioned, one necessarily has to wonder how many of the dominant personas envisioned the reform of the Roman liturgy promulgated in 1970 and the sweeping consequences it would have across Latin Christianity. Without falling into the trap of trying to separate out an authentic or "real" liturgical movement or, worse yet, papal approved (weren't they all?) from an imposture, one cannot ignore that the movement eventually found itself facilitating every sort of deconstructionist tendency in late modernity.
In liturgical studies, as with other facets of theology and other areas of intellectual life, there were numerous subtle currents heading in the direction of deconstructionism worthy of Derreda. Ultimately, Vatican II's attempt at reconciling with modernity proved to facilitate the near total absorption of such tendencies. As such, it is impossible to avoid the sharp contrasts in worldview and liturgical theory between someone like Schuster or Virgil Michel and their successors, someone along the lines of Jungmann or Bugnini. Whatever points of departure Schuster or Michel had from Catholicism's classic medieval worldview and corresponding (rich) spirituality, neither man lived to see the total assimilation of modernity or live and breathe in such a context.
Perhaps it is disparaging to the legacy of both men to suggest as much. Yet, both men (among others) are roundly considered foundational pillars of a school of modern liturgics that avoids coherence with the Latin Tradition and prefers keeping pace with current sociological trends. Perhaps they are considered outdated or even quaint, subject to self-imposed limitations, but they are invariably considered part of the modern canon.
Yet, labeling either man as "modern" may well be overreaching. Both men clearly broke away from stale "Tridentine" liturgics and, so far as I've been able to determine, advocated for a liturgical praxis (not necessarily a re-ordering of the Missale Romanum) that called to mind earlier periods of liturgical celebration.
So where does someone like Schuster fit? A modern? Perhaps, but can we really see a contemporary liturgist speaking in such terms? A pre-modern Traditionalist? Perhaps, but his liturgical vision was substantially richer than much of what came about as a legacy of Trent.
The allure of someone like Schuster is that one can only conclude, if one is honest, that his vision was a blessed accident of history. His intellectual prowess provided the means of communicating a liturgical theology (maybe even spirituality) that outshone the manualist tendencies borne from neo-scholasticism. He was, thankfully, spared from exercising such prowess during the great compromise with modernity - God only know what his theory would have turned into had this not been the case.
It remains to be seen when and if his vision can be retrieved from the annals of history and if its reality can ever be rediscovered.