It's not like God handed the completed work to some guy on a mountain like he did with Moses and the 10 commandments.
I just have always found it interesting that we believers seem to believe that no one in the last 1900 years has written anything God inspired that could be added. And why do we only study these letters assembled by the Catholic church to the virtual exclusion of all else.
I assume from what you wrote that your a protestant (as am I). How come we don't study the writings of Martin Luther or others which formed the basis of all protestant denominations in our sunday school classes? Are there no God inspired protestant writings?
Check your history. The OT canon was affirmed by Christ in Luke 24. The NT canon was set based on apostolic authority. Meaning the early church had a very good understanding which books or epistles came from actual apostles who walked with Christ or received direct revelation as in the case of Paul.
I find it interesting Catholics try to corner the market on the early fathers as do the Orthodox. They were pious studious men who could hear the Good Shepherd’s Voice in the Gospels of John, Mark, Matthew and Luke but not in Thomas and others. There was also an unbroken chain in the use of what became the NT canon. Just after John’s death we see in Polycarp’s epistle to the Philippians the extensive use of what we call the NT Scriptures. Check this out:
http://www.ntcanon.org/Polycarp.shtml
Now to address this using an analogy. We as Christians believe all Scriptures are inspired by God. He, so to speak, is the “Artist.” When we go to the Louvre we are awed by the wonderful works of art. We expect to see works of art from Leonardo Da Vinci, Michelangelo and other great artists. Since these great works reside in the Louvre does it mean the Louvre is responsible for making the works of art? Of course not, but we thank the Louvre for having a keen eye for art which the curators were taught to look for.
So the early church fathers did not make the scriptures authoritative. They were already authoritative because they came from the “Artist” God.