How do you think God has preserved the "originals"?
When the churches received the letters from Paul, Peter, John, etc. they made copies of them to share with other churches and so forth. The New Testament literally exploded across the Roman Empire as copies of the letters of Paul, Peter, Luke, etc. found their way in far remote areas bringing forth the light of the gospel in a very short amount time. In this way God protected the NT text from the one thing no one would be abe to detect: the wholesale change of doctrine, or theology from what was originally given. By the time any ecclesiatical organization acheived any world wide influence or power, important manuscripts such as
p66, or
p75, were long buried in the sands of Egypt, or others were so far removed to the most remote places on Earth that no one but the people who had them knew anything about it.
In this way God preserved his word in its theology & doctrine.
The flip side of this is the amount of variation that can creep into the text. Variations can come in the form of word order ( such as Christ Jesus, to Jesus Christ) , added titles ( such as from Jesus Christ to
the Lord Jesus Christ ) , importation of passages from other parts of the NT into a particular text, for the sake of "harmonization." etc. Once a variation gets into a text, it doesn't go away, it gets copied, & recopied,
ad infinitum. This is one of the reasons that God has raise up some to be teachers, so that we can be better equiped to understand the word of God. And I thank God for such teachers, like "filo" who come in here often, or others like James White, Kenneth Wuest, Tim Lahaye. The church today has been abundantly blessed with such an anointing of teachers that we should take advantage of what we have while we have them.