If families prayed this prayer daily, much could be changed.

Maybe the 75 years did not begin until 1962 (with the time between Pope Leo's vision until the Council simply being the dress rehearsal)?

I was thinking 2033, 75 years after Pope Pius XII’s death.

Yes, that's how I would date it, 1958.  One could conceivably start in 1955 or so also, when Pius XII's health deteriorated so much that he effectively let the Modernist-infested curia run the Church.  I personally believe that he was being poisoned, but that's pure conjecture without any evidence other than possibly the bizarre / mysterious behavior of his physician.  This same guy was selling deathbed pictures of Pius XII to European magazines.

In any case, what stands out for me is that Our Lady requested the consecration of Russia on June 13, 1929.  I expect something to happen on June 13, 2029.  Our Lord later appeared to Sister Lucia and compared the popes' refusal to perform the consecration to how the kings of France refused to consecrate France to His Sacred Heart.  Well, in that case, 100 years to the day that consecration was requested, Louis XVI was deposed.

October 13, 1884 (date of Leo XIII's Vision)

October 13, 1958 (date of Pius XII's burial) --75th year begins

January 25, 1959 (John XXIII called Vatican II) -- 75th year
https://www.papalartifacts.com/january-25-1959-pope-john-xxiii-stuns-the-world/

January 25, 1983 (John Paul II promulgates 1983 Code of Canon Law) --100th year
Sacrae Disciplinae Leges



https://anonymousprophets.wordpress.com/pope-leo-xiii/the-vision/


The Vision – 13th October 1884


Exactly 33 years to the day prior to the great Miracle of the Sun in Fatima, that is, on October 13, 1884, Pope Leo XIII had a remarkable vision. When the aged Pontiff had finished celebrating Mass in his private Vatican Chapel, attended by a few Cardinals and members of the Vatican staff, he suddenly stopped at the foot of the altar. He stood there for about 10 minutes, as if in a trance, his face ashen white. Then, going immediately from the Chapel to his office, he composed the prayer to St. Michael, with instructions it be said after all Low Masses everywhere.

When asked what had happened, he explained that, as he was about to leave the foot of the altar, he suddenly heard voices – two voices, one kind and gentle, the other guttural and harsh. They seemed to come from near the tabernacle. As he listened, he heard the following conversation:



Let us think about this for a minute.  This happened in 1884.  The devil said he needed 75 to 100 years.  Well, 75 years from 1884 is 1959.  Wow, what a coincidence that it was on January 25, 1959, that John XXIII publicly summoned the Second Vatican Council. Remember that after the vision, Pope Leo XIII immediately wrote the Prayer to St. Michael to help us overcome the devil in his quest.  He instructed that it be said after every low Mass.  One of the first changes to come from Vatican II, was the deletion of the Leonine Prayers which included the prayer to St. Michael.  These prayers were eliminated in 1964, the 80th year of the devils 75 – 100 years needed to destroy the Catholic Church.  It would seem that this would be the time to especially say that prayer, not to delete it. The 100th year would be 1984.  By 1984 John Paul II had let the devil develop a church that is called Catholic, but is not. The devil has twisted and distorted church teachings so much that there truly is a brand new church, a new order (Novus Ordo) and the true church has been reduced  in population to a mere shell of what it once was, but it will survive:

Also, a little over year and a half later, JPII's decision to allow the "indult" of the Traditional Latin Mass:

October 3, 1984  Quattuor abhinc annos

https://archive.ccwatershed.org/media/pdfs/19/10/24/19-52-37_0.pdf