Good points, Dogmatix...oops, I mean OrthoCat lol.
I would add two points:
1. The modernists first removed the tabernacle from the altar and put the tabernacle in a corner to de-emphasize the Blessed Sacrament being the centre and visual focus of attention in Catholic churches. They put the priest's chair where the altar and the tabernacle were--where God was.
Then they separated the Word of God from the Altar of Sacrifice as the readings were done from the altar not from the 'ambo'. Once the Word of God was separated from the altar, they turned the altar of sacrifice into a memorial table of thanksgiving. Then they gave equal status to the Word of God ambo as to the memorial table to the extent of putting two candles permanently beside the ambo. And voila...the modernist liturgical revolution is a fait accompli. Protestant Reformation bis.
2. The modernists want us to feel guilty if Mass is offered without a "homily" or without a "congregation in attendance." This leads us to the question: What is the Holy Sacrifice of the Mass fundamentally as a whole, and in its separate parts?
In Catholic theology, propitiation refers to the doctrine that original sin, and mortal sin are infinite offences against the Infinite Majesty of God. Our Lord Jesus Christ's sacrifice on the Cross was required by God to satisfy His Infinite Justice once infinitely offended by mankind's sins, and required by God to reconcile humanity to God. Our Blessed Lord, God Incarnate, is both True God and True Man.
Only Our Divine Savior could Infinitely merit Infinite Atonement for our sins by His Death on the Cross as only He is a God-Man. Also, by not sparing His Only Begotten Son, while sparing Abraham's son, Isaac, God wanted to teach us to have horror for sin, and that each mortal sin is an infinite offence against the Divine Majesty of God that no human person could possibly atone as it required an equal and opposite infinite act of atonement that only a Divine Person, the Second Person of the Blessed Trinity, God Incarnate, could perform. Propitiation is a theological term used to describe the atoning sacrifice of Christ, which appeased God's wrath and restored humanity to a state of grace, impossible without the Redemption.
This doctrine is rooted in Sacred Scripture in the Old and New Testaments and has organically developed in precision and in depth over the centuries influenced by the theological insights of Doctors of the Church, and holy theologians throughout Church history, including St. Thomas Aquinas.
Propitiation is a central tenet of Catholic faith and practice.
Just Christ is One Divine Person, the Church teaches that you cannot separate the tabernacle with the Reserved Sacrament from the Altar of Sacrifice, nor can you separate the Word of God from the Altar over to a separate and equal 'Ambo' from that same Altar as if the Eucharistic Sacrifice and a sermon were equal. The united "Altar of sacrifice-Tabernacle of Repose- and the Word of God proclaimed from the Altar" symbolize one reality only, one thing only: Our Lord Jesus Christ, the Word of God, Our Redeemer, Whole, Entire, Undivided, Body, Blood, Soul and Divinity. Who but the devil would dare separate that ONE REALITY into disparate, jarring parts?
The Doctrine of Propitiation in Catholic Theology and in the Mass
It is important to note that the Catholic doctrine of propitiation does not imply that God is angry with humanity in a personal sense. God's wrath against evil however is real ie. Noah's Arch and the Great Flood, Sodom and Gemorrah, etc. God cannot be Infinitely Good, nor Infinite Love. If God did not hate evil. Anger in God is not passion as with men. Anger in God is action against evil through miracles and judgement. God would contradict His Own Essence and Being in that case, and would cease to exist due to the principle of identity, and of non-contradiction. We should not anthropomorphize God's anger and equate it to human anger. Hence, we can say that God's wrath against the sin and iniquity of mankind, in a general sense, is real, and is appeased once and for all by Christ's sacrifice on the cross, and is continues to be appeased each time the Redemption is applied to us again here in time by the continual offering of the Holy Sacrifice of the Mass all over the world.
This Catholic doctrine of the Holy Mass being a propitiatory sacrifice with salutary effect was rejected by the Protestants as for Luther all human works are sinful and bad, as man's human nature is corrupt, and, as a result, all of man's actions are worthless, without effect, and are sinful and bad including the Sacrifice of the Mass. The doctrine of propitiation demonstrates the seriousness of sin and the necessity of divine intervention to restore the broken relationship between God and humanity. The Mass is first and foremost a re-enactment of the self-same Sacrifice of Christ on the Cross, re-presented in time, by the priest who stands "in the person of Christ"--alter Christus--. The Sacrifice of the Mass applies, in time, the actual merits of the Redemption, won by Our Lord on the Cross, to our souls today. Therefore, the Mass is not a pedagogical tool. The Mass is the Sacrifice of the Altar. We do not say: "Preaching is the Mass". To separate the Word of God and the Altar is blasphemy and sacrilege. This is what the Protestants did when they rejected that on an altar a true propitiatory sacrifice is offered. That's why they dismantled and separated everything. Preaching at Mass to the people if they are present is a pastoral opportunity that can edify, educate and inspire them...but it is not NECESSARY per se. A sermon at Mass is opportune or not depending on the circumstances. The redemptive value of one Mass, in and of itself, is infinite and suffices unto itself. Therefore, the more Holy Masses offered by priests the better as more graces will rain down on the Church, and the Souls in Purgatory, for example. The New Mass has killed devotion and obligation to succour the Holy Souls in Purgatory. Each and every Mass offered is of inestimable value to God, to the Church, and to us; hence, our Mass intentions, for example.
St. Peter's Basilica used to have separate Low Masses offered at the many side altars every day. 'I Con-celebration' killed that off after the Council. Pope Francis killed off con-celebrations after that. St. Peter's has become Haga Sophia bis...a museum. Monasteries had multiple side altars as well so that each monk priest could offer the Holy Sacrifice at the same time as 'con-celebration' is not the standard in the Western Church except at priestly ordinations. In the Eastern Church, concelebration is the standard.
Mass Chantries in England at the time of Henry VIII offered Requiem Masses, like multiple Gregorians over many decades, supported by wealthy benefactors. These priests were 'mass priests'. They were ordained to carry out the key function of the sacrificial priesthood, to offer the Holy Sacrifice of the Mass...alone. The Mass is itself literally a sacrifice, therefore propitiatory; but it's not literally the same the self-same event in time as the Sacrifice of the Cross, since our Lord does not die again at Mass, but it has the self-same effect of the Sacrifice of the Cross...every Mass. The Mass offers propitiation to God, or the infinite atonement of the Satisfaction of Christ's Sacrifice on the Cross which "makes whole", offers infinite reparation for the infinite offense of sin to God. The Mass is an act of infinite propitiation to God for the sins of all of mankind from the first sin of disobedience to the end of the world. So the Mass is a literal visible sacrifice, which represents and 'applies the merits' of the literal, once-for-all sacrifice of the Cross.They did not preach. They did not have congregrations. Why? Propitiatory sacrifice was offered by Abraham of his son Isaac in the Old Testament. The patriarch's sacrifice had value only in so far as they prem-figured and symbolized Christ's future sacrifice on Calvary. Circumcision was a pre-application of the future merits of the sacrifice of Christ in the Old Testament. This pre-application was salutary for the Jews. In Catholic doctrine, propitiation is defined the sacrifice of Christ on the Cross redeemed mankind 'in potency', and the Sacrifice of the Mass applies 'in actu' the salutary effects of the Redemption to mankind, the propitiatory sacrifice of the Mass also calms God's wrath, which satisfied God's justice and resulted in God being favorably disposed towards people.Catholics believe, unlike Protestants and modernists, that the Holy Mass is a 'propitiatory sacrifice' which means a good spiritual action, or work, which has a real, salutary effect of atonement.
Bugnini and his Protestant Liturgical 'periti' Visigoths pulled 'concelebration' from here, and the Canon of Hippolytus from there, and again Communion in the hand from some other time, somewhere else. All were discarded by the Church.
Conclusion:
It is not essential to the holy rites that there is be a sermon at every Mass. The Mass is first and foremost true pleasing worship offered to God. It is not first and foremost a pedagogical tool for education, only indirectly. Christ did not come just to preach, although preach He did. Our Divine Saviour came to redeem the world, and to apply the potential Redemption of the Cross through the Seven Sacraments, especially through the Mass, the Sacrament of His Body and Blood, the potential Redemption made actual in our lives when we accept the graces that flow w through the Holy Sacrifice. The Mass is 'deocentric' not 'anthrocentric.' First and foremost, we participate fully in the priest's offering of the Holy Sacrifice of the Mass by uniting ourselves spiritually and invisibly along with the whole Church to what is occurring: the re-presentation and re-application in time of Christ's great and Infinite Redemptive Act of Divine Love to atone for mankind's sins which represent an infinite offence against the Divine Majesty. In fact, a sermon might even be inappropriate at some Low Masses especially given the cases I have outlined above.