The answers are in these three short paragraphs:
DEVELOPMENT OF DOCTRINE
from The Map of Life by Frank J. Sheed
ewtn.com/library/spirit/maplif.txt
The Church then, 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
[ossification]. 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. This development in the Church’s understanding of what has been committed to her is not like anything else in the world. Science, for instance, progresses, but its progress consists to a large extent in discovering and discarding its own errors. The teaching of the Church develops by seeing further truths. At every stage the Church adds something: but not at the cost of discarding anything. At every stage all she teaches is true: at no stage does she teach all that is contained in the Truth.
This development–which we find in theology and nowhere else–combines two things: the work of men’s minds, the over-ruling protection of God. In theology, as in science, progress comes by the minds of men working on what they have been taught: but left to themselves, men may simply make further mistakes. In science they do so. In the teaching of the Church they do not: and the reason is that God intervenes, to prevent the teaching of error by His Church. God’s actions–whether revelation or sacrament or miracle-- are never labour-saving devices: God does not do them to save men the trouble of doing what they can very well do for themselves. In revelation, for instance, God teaches men what they could not (at any rate could not with absolute sureness) find out for themselves: but having given them that, He leaves it to them to meditate upon it and arrive at a clearer understanding of it. He does not do their thinking for them.
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So, it’s not an “obsession with novelty”. It’s an awareness that development happens as we (your own theologians included) think about and pray about what God has revealed to us.