I think they were done away with in '64 because they were devotional prayers not the public prayer of the Church, in Ireland there was a custom of saying the Psalm, De Profundis, as well after Low Mass. Didn’t John Paul II call for the Prayer to St.Michael to be said after the Novus Ordo Mass?? If you notice at a TLM the priest will make the sign of the cross before and after the sermon, some times might say a Hail Mary, now priests don’t do this as much because these prayers have their origin outside of the Mass.
God Bless