"They were to be read in the Church but not depended on for doctrine."
But, see, Jerome was not the fellow who compiled the Bible.
He was just the fellow who translated it into LATIN for the West to use.
There were councils and synods before Jerome, at which the books of the canon were discussed. The texts from these councils and synods are available online, and when you peruse any of them, you will see that they varied in their content of Old and New Testament. You will also see that all of them included some of the Deuterocanonical works in their view of the Canon. With Damascus' list, the canon remained that, and that was what was ratified at Trent.
Remember that you come at this from the cultural perspective of a Protestant, and for you, the Bible is THE thing. But that is not true of Catholics, and it most certainly wasn't true of the Catholics back in the 300s and 400s. They were not straining to get to a settled Canon so that, finally, they would all have a text to agree upon and then do the sort of parsing of the texts that a good Evangelical Bible-bash does today. The Canon of Scripture was always there, but the Bible was never the primary evangelical tool of the Catholics. Charitable works, and caring for the sick and the poor, and schools - Mother Theresa stuff - was always the way that the Catholics (and the Orthodox, which are one and the same when we speak of 400 AD) implanted themselves (once Catholicism was legal, and even before that).
The particular, singular focus on the BIBLE and on written texts and canon and parsing out particular phrases like a Talmudic scholar: this never was a Catholic forte and still isn't. Remember that there was no Protestant Church then. The Catholics were not struggling against folks like you who thought the way you do. They were struggling against folks who denied the Trinity entirely, or denied the divinity of Jesus, or denied that women had souls, or denied the Resurrection, or who claimed that the whole Jewish Law, lock, stock and barrel, applied to Christians.
There was some appeal to Scripture, to be sure, but not as something utterly apart, separate and distinct from, or indeed antithetical to, tradition. The Scriptures were simply a part of the tradition. Now, the idea that Catholic traditions are the modern equivalent of the traditions of the Pharisees which Jesus excoriated is a modern, Protestant one. There was not that dichotomy of strict textualists versus traditionalists back then. This is why, from one raised in a Protestant tradition where the Bible is something of a CONSTITUTION for the Church, the lackadaisical Catholic approach to the Biblical canon over the course of history is disorienting. Obviously in modern times, Protestants use the Bible to distinguish themselves from each other, and from the Catholics. It is only natural, if one is in that tradition, to retroject it to Jerome, and to see a guy struggling for the purity and truth of Scripture against the "contamination" of tradition, which is viewed as bad.
But truly that was not the mindset of the times. Jesus excoriated the Pharisees traditions. He was aiming at the Pharisees, not condemning all traditions for all times. Indeed, Paul's letters flat out instruct his churches to follow the traditions he taught them. Tradition is GOOD, in Scripture, if it's proper apostolic tradition.
Jerome was not a struggling Luther. Remember, Luther thought passionately enough about the Scripture business to secede from the Church itself rather than submit to what he perceived as evil threatening to dilute the purity of "God's Word" in Scripture. Jerome preferred the Jewish, Hebrew text over the Jewish Greek text, and said so. But when he was told to put the Deuterocanonica in the Vulgate translation anyway, he did not raise a gargantuan theological fuss over this, as though this would somehow contaminate the only place where the pure "Word of God" could be found.
Why?
Because Jerome was a Catholic, and like all of his contemporary bishops and doctors of the Catholic Church, thought that the pure Word of God ultimately reposed in the Holy Spirit upon the Church. He had his opinions about which sources were better for translation, but he believed that the Church had the authority to decide, not him, and obeyed the Church, which is to say that HE thought that the tradition was more authoritative than the texts he was translating.
And that is very Catholic: the Church is the authority. The Bible has authority because it comes from the Church. Independent of the Church, the Bible is good reading, but if interpreted outside of the canons of the Church, or against the Church, it can become a force even for evil. "The Devil can quote Scripture to suit his purposes."
So when you speak of "Rome, in this instance, won the day" when speaking of Jerome, you are retrojecting the views of the 20th Century onto the 5th. The difference between Jerome and you is fundamental on this. Jerome thought that the Pope and the Church had the authority over the book, and acquiesced. You would consider that to be marring the Word of God, and that the Church must absolutely be submitted to the authority of the Bible.
Which is to say Jerome was a Catholic, and you are a Protestant. There were no Protestants in 400 AD. There was no Christian on Earth who held up the canon of Scriptures and asserted that this superseded the traditions of the Church. The world of Jerome would not be recognizable to modern theologians. All of the reference points were not there. Christianity without a fixed Bible, was a Christianity in which the Bible was not very important. To a cradle Protestant, that's a scary world. But it is as it was.
"Jesus said, "The scribes and the Pharisees have seated themselves in the chair of Moses" (Matthew 23:2)."
True. But Jesus also performed a miracle in order to pay the Temple tax. And Jesus, after performing a healing, sent the man to the Temple to give the customary sacrifice to the priests and scribes.
In the Torah, Reuel tells Moses he can't judge all the people, and tells Moses to set up judges of the subdivisions of the people, and he does. The Torah explicitly gives the religious authorities the power to judge, to decide, from which there is no appeal. Likewise, whatever Jews personal relationship with God, they were also required to properly offer sacrifices through God's priests. Paul explicitly accepts the authority of the High Priest and the Sanhedrin.
Remember that Pharisees were NOT priests. Neither were scribes. The former were civilians full of religious zeal. The latter were religious scolars and functionaries. The sacerdotal offices were in the hands of the priests, whose function and authority was absolutely spelt out in detail by God in the Torah.
Paul spells out, (but does not create!), the Christian tradition of handing down sacerdotal authority to bishops and priests and deacons by the laying on of hands.
As to this part: "I agree with your comparison regarding the authority of the Sanhedrin and High Priest to interpret the Torah, and 'the Pope and the Vatican Curia'. Christ gave neither the authority to blend men's traditions with Holy Scripture."
Holy Scripture IS the tradition of men.
Paul says differently when he explains what the tradition is that he is teaching.
Galatians 1:11-12
"I want you to know, brothers, that the gospel I preached is not something that man made up. I did not receive it from any man, nor was I taught it; rather, I received it by revelation from Jesus Christ."
Matthew 23:1-3Indeed, Paul's letters flat out instruct his churches to follow the traditions he taught them. Tradition is GOOD, in Scripture, if it's proper apostolic tradition.Then Jesus said to the crowds and to his disciples: "The teachers of the law and the Pharisees sit in Moses' seat. So you must obey them and do everything they tell you. But do not do what they do, for they do not practice what they preach."
Acts 23:4-6
Those who were standing near Paul said, "You dare to insult God's high priest?"
Paul replied, "Brothers, I did not realize that he was the high priest; for it is written: 'Do not speak evil about the ruler of your people.' (Ex 22:28)"
Then Paul, knowing that some of them were Sadducees and the others Pharisees, called out in the Sanhedrin, "My brothers, I am a Pharisee, the son of a Pharisee.
2 Thessalonians 2:15So then, brothers, stand firm and hold to the teachings we passed on to you, whether by word of mouth or by letter.