Balance out economy by having competition since the world is kind of organic, if you begin farming to "Farm" money, a NPC could possibly undercut you with lower prices to product, so you'll have to adjust what you sell..a smart competitive economy can make things interesting.
I totally agree! I'm definitely drawn to games that have dynamic / organic systems like what you're suggesting here. A competitive, dynamic economy would definitely make running a business sim even more satisfying to play hours and hours on end - forcing the player to be strategic about which items to craft or materials to find (based on whatever the current demand looks like).