As you can see from the foregoing, the pertinent legal/canonical principles that justify not using the 1955 Holy Week are:
(1) Lack of Stability, i.e. the legislation lacked one of the necessary elements for a law, stability, because it was transitional in nature and intent, and
(2) Cessation, i.e., a human ecclesiastical law that was obligatory when promulgated can become harmful (nociva) through a change of circuмstances after the passage of time; when this happens, such a law ceases to bind.
These general principles may be applied to decrees promulgating liturgical laws, including the new Holy Week, because (1) the legislation was transitional in nature, in intent and in fact; and (2) the many parallels in principles and practices between the Missal of Paul VI and the 1955 reforms now render continued use of the latter harmful, because such a use promotes (at least implicitly) the dangerous error that Paul VI’s “reform” was merely one more step in the organic development of the Catholic liturgy.
It seems that every and any new law lacks stability, including of course, the fast mitigation under Pius XII.
The same arguments posed by Fr. Cekada could be applied to
Divino afflatu, since the reforms of the Roman Breviary were never finalized.
From the tome
The New Psalter and Its Use by Rev. Frs. Edwin Burton and Edward Myers (pp. 43-44; London: Longmans, Green & Co., 1912):
On the publication of the new Psalter Pius X announced that a Commission would take in hand the complete reform of the Breviary. According to Mgr. Piacensa this will involve:
(i) A reform of the Calendar and the fixing of criteria of admission of feasts of saints into the Calendar of the Universal Church.
(ii) The critical revision of the historical lessons of the Breviary.
(iii) The removal of spurious patristic lessons and the correction of the text of the rest.
(iv) The remodelling of the General Rubrics.
(v) The institution of a common of many confessors and a common of many holy women in order to facilitate the lessening of the number of feasts of saints without injuring devotion to the saints. [emphases mine]
Only the fifth objective listed above was accomplished, and even then these Common Offices were conceded only to certain localities: never did they form part of the Roman Breviary itself. The previous four objectives were never accomplished. Even the General Rubrics were left untouched, and a supplement to them was inserted with the new rubrics promulgated by Pope St. Pius X and the Congregation of Sacred Rites availing itself of his authority.
Are we then free to invoke
epikeia and revert to the typical editions of the Roman Breviary published during the reign of Pope Leo XIII? Or maybe that's not far back enough...
It was Pope St. Pius X who made
the most revolutionary change in the Roman Breviary (
op. cit., 44-45):
The advisers of Pius X, however, have gone to the root of the problem and have eliminated one of the great causes of the interference of the festal office with the ferial office, viz. the undue length of the ferial office which on certain days made its recitation very burdensome, and by redistributing the Psalms have rendered possible the frequent realization of the liturgical ideal of the weekly recitation of the Psalter.
One cannot but rejoice in the restoration to its place of honour in the prayers of the Church of the book on which the piety of generations of her sons has been been nourished. Many, no doubt, will regret to see the old Roman arrangement of the Psalms disappear after having survived so many reforms, but their regret will be tempered by the thought that practically it had already disappeared, since its use had become so rare
Where are the "many" who regretted the loss the ancient Roman Psalter now? Did they react to the
new Psalter of Pope St. Pius X as Father Cekada et al. are reacting to the reforms of Pope Pius XII?