"Life in the countryside is pure hell. Local businesses know where the money is, and essentially what kind of shopping experience they want their customers to have."
Boy, your experiences have been vastly different than my own. Rural communities are far more decentralized and interdependent, and I find patronizing local businesses strongly reinforces communities, rather than facilitates predatory business practices.
"What about sea trade? Sea trade is far less reliable and is unpredictable."
Long distance trade is hugely dominated by sea routes, and has been long into prehistory. However, it is only available to institutions well organized, and anyone can walk next to a camel for 3000 miles, making land routes primarily valuable for commodities and individual traders.
As always, I deeply appreciate your post. You put a great deal of thought into them, and grasp well our political exigency.
Thanks!