Point to consider: If we found an ancient manuscript of a portion of God’s word, and this manuscript was considerably different than what we’ve recognized as God’s word throughout the centuries, rather than embracing the new text and altering our Bibles, we would keep our current reading. Why?
It is a fundamental tenet of the faith that God keeps His word preserved and pure throughout all generations. This means that the word is preserved through being used by the Church. It is duplicated and distributed, and this is the process through which God has seen fit to preserve His word. The preservation of the scriptures has never been about maintaining a set of “originals”, obviously, because no originals exist! So we use what we have received, being trusted, and not that which is “lost and found,” being suspect.
Chiefly, this is a matter of faith. The church is “the pillar and ground of the truth.” This means the truth is preserved in the church. Libraries, museums, and universities are not Divinely charged with this task. It’s the job of the church. And we trust that God has preserved His word through the duplication and usage within the institution of the church.