Supposedly Christians are a banned sect in the first century being killed by the thousands by the Romans. Perhaps many were on the run, but you tell me they are sending their letters via the mail belonging to the Empire, the very empire trying to kill them ? Doesnt sound very smart.
Do you think the jews were sending open letters talking about Jewish matters via the Nazi mail ?
SOmething doesnt add up.
I don't think you've thought this through very well.
There were people who, for a small fee, called an emanuensis, would write letters FOR you and also READ them.
Think of it this way, Today if you need a legal contract and can't write one yourself--what do you do? You pay and attorney to do it for you.
We were clearly talking about regular letters not ones constructed by solicitor types. As we both know these services are not free, which again brings up the matter cost. I know you brought up the matter of a wealth benefactor, and that could happen. Strangely this arrangement along with the money were never mentioned in any of the letters.
Even aborigine tibes in America could communicate with drums and smoke signals.
Smoke signals dont work cross country. Im pretty sure tehre are no exampkes of an entire chain of indians crossing hundreds of km.
Carrier pigeons with a message could carry messages long distances.
How exactl is a pigeon going to carry an entire scroll the size of any of the books we have in the Bible. The poor thing can only carry a few words. To send any Pauline book would require a squadron of pigeons. There has never been an example ancient or modern of pigeons flying the distances that you claim. If a network did exist the cost would be prohibitive.
Ships at sea used semaphores.
Semaphores require a ship every 3km or so. I mean comeone are we to believe they had thousands of ships bobbing up and down from Rome to Alexandria or any other major networks.
If we look at the end of the war of 1812, we cansee even the British EMpire didnt have any of the comunication systems you claim existed in ancient Rome. They sent messagse the old fashion way by ship.
There are many examples of battles months after are a peace has been negotiated somewhere else in the world in ancient times before the telegraph.
On December 24, 1814 the diplomats had finished and signed the Treaty of Ghent. The treaty was ratified by the British three days later on December 27    and arrived in Washington on February 17 where it was quickly ratified and went into effect, thus finally ending the war.
American victories in September 1814 and January 1815 repulsed all three British invasions in New York , Baltimore and New Orleans.
Your examples are nonsense, unpractical and just dont work.