But more to the point, it goes without saying that the requirements for salvation have changed. 450 years ago God was ignorantly letting people into Heaven even though they didn’t believe the Marian dogmas, which are now required. 450 years ago, one didn’t even have to believe in papal primacy - that only came in 1870.
This is an empty argument, and you know it.
First, the Marian dogmas were not invented out of thin air; they simply formalized long-held beliefs of the people. The same could be said of papal infallibility which you have dated to 1870.
Second, please allow me to assure you that I have spent weeks in the Eastern Catholic forum arguing with Orthodox about the primacy and supremacy of the Pope, and while none of them would concede on supremacy, ALL of them would be quick to take up the argument against you concerning primacy. You are simply spouting nonsense here, and you know it.
Ideally, salvation should be through trust in Christ. Not an ever-growing list of intellectual assent. Paul says of his time in Corinth “I resolved to know nothing while I was with you except Jesus Christ and him crucified.” ( 1 Corinthians 2:2) To a modern Catholic that must seem like a rather thin message - no mention of the Church.
Yes, doctrine develops. Those who come later stand on the shoulders of those who went before. Some Christians lived before the development of the canon, others before the various heresies concerning the incarnation had been defeated. But once these things are firmly settled, then yes, orthodoxy requires the assent of faith to them all.
But Catholicism has developed. Despite what Vatican 1 said. The “truths required for your salvation” haven’t always been in place. I’d like the requirements for salvation to be unchanging, because God’s laws, as a reflection of His character are unchanging. But that’s not the case in the RCC. There have certainly been additions. How do you handle those? When asked, “What must we do to do the works God requires?”, Jesus answered, “The work of God is this: to believe in the one he has sent.” Didn’t Jesus know about the other required beliefs?
I suspect the Jews share your feeling that God keeps moving the goal posts.
The Church, by the time the last apostle died, had all the mass of truth the apostles had taught, the whole of it by word of mouth, a part of it in writing. She might have simply gone on, through the nineteen centuries since, repeating what had been taught, reading what had been written. In this case she would have been a preserver of truth–but scarcely a teacher. She would have been a piece of human machinery, but not a living thing, not the Mystical Body of Christ.
In fact, she not only repeated what the apostles had been taught: she thought about it, meditated on it, prayed by it, lived it. And, doing all this, the Church came to see further and further depths of truth in it. And, seeing these, she taught these too. Everything was contained in what Christ had given the apostles to give the Church: but though everything was there, it was not all seen explicitly–not all at once.
A rough comparison may make the position clear: a man brought into a dark room begins by distinguishing little: then he sees certain patches of shadow blacker than the rest: bit by bit he sees these as a table and chairs: then, as his eyes grow accustomed to the obscurity, he sees things smaller still–pictures, books, ash trays–and so on to the smallest detail. Nothing has been added to the contents of the room: but there has been an immense growth in his knowledge of the contents.
So with the Church. She has, generation by generation, seen deeper and deeper.