|A complete Isaiah, c. 100 B.C. - 50 A.D.|
You claimed that Christianity lived on "oral cultures for the better part of a century without the full benefit 'of its sacred texts' and for centuries without either an Old Testament or New Testament canon."
That's simply not true.
You admit that the early Church had the Septuagint and the writings of the Apostles, the documents that form Christendom's canons (plural, which I'll discuss later). That was during the lifetime of the Apostles. Unless they lived for "centuries" and didn't compose their Gospels and Epistles until the ends of their lives, the Church had the "full benefit" of its sacred texts in the first century.
A few examples:
-Galatians was authored c. 51-53 a.D. That's less than two decades after Christ's ascension, not "the better part of a century."Since you're focusing on "canon" as in some grand poobah/council declaring something official (are you repeating the Muslim lie regarding Nicaea?), then it's clear that you misunderstand the term. "Canon" simply means "measure" or "rule." If it's something official you want, then the Church had -- and has -- no "canon." Luther struggled with James (and a few other books). In reaction to Luther's rearranging of the apocryphal books as an appendix in his translation, the Church of Rome declared certain texts "canonical" which even Jerome, the translator of its official Bible, considered less-than-inspired. And what of the rest of Christendom?
-Papias referred c. 125 to the Gospel of John (c. 90). That's less than one century after Christ's earthly ministry, not "centuries."
-The last document to be received by the Church was John's Revelation, c. a.D. 95. That's less than six decades after Christ's death and resurrection. (And the reason that it came so late is because John did not receive it until then).
There is no one, official "Canon" (though there's a lot of overlap). Depending on whom you ask (Roman Catholics, Protestants, Greek Orthodox, Slavic Orthodox, Armenian Orthodox, or Ethiopian Orthodox?), you'll get varying canons. Does that mean that the Church has gone two thousand years "without the full benefit 'of its sacred texts' and [. . .] without either an Old Testament or New Testament canon"?
One last point: Considering that the Apostles used the Septuagint and many of the "reformers" were actually "deformers" [heretics], it seems to me that Reformation-era opinion is, for the most part, irrelevant.