Pope Francis: “St. Paul VI, recalling that the work of adaptation of the Roman Missal had already been initiated by Pius XII, declared that the revision of the Roman Missal, carried out in the light of ancient liturgical sources, had the goal of permitting the Church to raise up, in the variety of languages, ‘a single and identical prayer,’ that expressed her unity. This unity I intend to re-establish throughout the Church of the Roman Rite.”
[Letter accompanying Traditionis Custodes]
Pope Francis: “those who are rooted in the previous form of celebration and need to return in due time to the Roman Rite promulgated by Saints Paul VI and John Paul II” [Ibid.]
Pope Francis: “The liturgical books promulgated by Saint Paul VI and Saint John Paul II, in conformity with the decrees of Vatican Council II, are the unique expression of the lex orandi of the Roman Rite.” [Traditionis Custodes]
Pope Francis intends to re-establish throughout the Church of the Roman Rite a single liturgy, the Novus Ordo, just as Pope Saint Paul VI did (or at least attempted to do) in 1970. Those who are still permitted to celebrate the TLM must “return in due time” to the Novus Ordo. The Novus Ordo will be the “unique expression” of the sacred liturgy in the Roman Rite.
Some Bishops are permitted the TLM, and some have already shut it down. I perceive a three step plan by Francis to entirely END the TLM (which plan may or may not succeed).
1. TC is used to shut down TLM is every diocese where the Bishops do not want the TLM and strongly agree with Francis in having one Novus Ordo. That is already happening.
2. The Holy See puts pressure on the Bishops who are supporting the TLM, and refusing to transition the traditionalists to the Novus Ordo. Bishops can be moved to a new diocese, forced to retire, suspended a divinis, or excommunicated. All the prudent Bishops who wish to remain in office, which is most of them, will gradually fall, one by one, and comply with the Pope. So eventually even TLM friendly diocese will not have the Latin Mass.
Do NOT underestimate any Supreme Pontiff. He holds the keys. He wields the two swords of the Church. Remember the news story in Chile? “All of Chile’s 34 Roman Catholic bishops had offered their resignations.” The Pope accepted three of them; he could have accepted half or 90% or all.
3. Then the only Latin Masses left will be in FSSP and ICKSP and similar groups. They are under the direct authority of the Holy See, not the local Bishop. But the local Bishop can kick them out of the diocesan churches. And eventually the Pope will bring an end to these Latin Mass groups. This might require a second Moto Proprio, ending the mission of the FSSP and other groups, or changing their mission to transition their faithful to the Novus Ordo. If they refuse, they will be suppressed.
If you think the Pope can suppress the FSSP, remember that the Pope once suppressed the Jesuit Order. Which group was bigger? The Jesuits. Which group had more power? The Jesuits. Which group was around longer? The Jesuits. The Pope suppressed them.
That is the likely (possible) three-step plan to END the traditional Latin Mass.