You might want to check this “It will take hundreds of years to have multiple copies circulating around the Christian world” ... depending upon the quantity you choose to name, there were within weeks, copies of the letters sent to a church, and these copies were distributed among the churches which were a mere 30 to 50 or less miles apart. A woman like Lydia, for instance, would have had a scribe working for her in business and able to clip off a dozen copies in a matter of a week and in another week have them circulating to the other churches. Something so prescious would not have been ‘stuffed under a bushel’. The Armenian Church, for instance, has copies of very early copies!
Does that make sense in the first half of the 1st Century?
Most of the Christians were illiterate and poor and could not support literate people to copy out many copies of letters by hand. Obviously some survived, but how many did not? Remember; no emails, no mass storage or production. The example of Lydia is an exception, rather than a rule. Plus, she was from Thyatira; I don’t recall an epistle sent there, so she may or may not have had access to any of any of the Apostles’ letters.