Most people back then knew the Scriptural text via the liturgy, not through having copies at home. And most of you, my friends, only know the Scriptures through translators. Translators who are fallible. And even those lucky few who can read Greek only know Scriptures through the manuscript evidence, which does not, I might point out, take us back to the original autographs of the Apostles but only to manuscripts which were copies of copies of copies.
None of us, I'm afraid, can claim a direct link to the Apostles via Scripture. We don't have Matthew, Luke, Mark, or John, or Paul in the originals. Any way you slice it, the Apostolic teaching had to reach us by being preserved and promoted and copied by those who lived after the Apostles. So the infallible Scripture doesn't get to us any other way but the ever-fallible hand of men.
You may say that God's ineffable wisdom deigned that it would be preserved, and preserved accurately. We agree. And He did so via the Church.
Literacy was much more prevalent in Europe before the Roman Church, which suppressed literacy for the commoner, came into power.
In the Eastern Orthodox areas where literacy was encouraged, many more common people were able to read the Bible and texts were numerous. Bibles were so common in that area that the EO Church, which believed the book of Revelations was written expressly for the church, excluded it from the Bible so that people would not have access to it.