Common sense. My home town of Pittsburgh had six newspapers in 1860. New York City must have had 20 papers catering to every party and ethnic group. It also had thousands of young boys who either delivered or sold on the street 99% of the newspapers. The US Mail service in 1860 was not much different than today -- first class delivery between say New York and Washington was at best 3 days -- i.e no longer "news". How much are you willing to pay for a 3 day old paper when even in 1860, there were "wire" (telegraph) servies that reported the exact same national stories accros the nation?
Surely, there were some out-of-town subscribers willing to pay for mail delivery who were living in another area and interested keeping in touch with home --- the death notices, marriage licenses and local political, business and social happenings that would not show in the papers where they were residing, just as relocated people today access on the Internet to their home-town paper to keep in touch. But if you think that any paper in the country relied on the US Mail service for the "majority" of their subscribers, and revenues, I'd say you are stuck on stupid!
To claim that "most" of any newspaper's circulation was dependent on a slow and unreliable US Postal service either in 1860 or in 2005 is simply absurd --- but then again Pea, so is most of your mythology. But in your favor, you are not nearly as absurd as Stand Watie. ;~))
Ahhh, that phrase again.