What I think would work is to have the population from each sector consume goods, and they would have an infinite wallet. The size of the local population for each sectors would dictate the demand for each of the goods. Their purchasing power would be a continuous source of revenue for the player or NPC selling to them.
The error in this model is that it ties the consumption of goods to a fixed credit amount. What if said goods are valued higher than the earned credits for the player/NPCs? Value is lost, and the economy would collapse, as the player/NPCs would lose money by selling goods for this consumption. If the value of consumed goods is priced lower than the money received, NPCs will accumulate more money than they can spend and will likely never run out. This is the same result as infinite money. In the real world, modern economies run on fiat currency, and money is infinite. Goods are finite, and this is the direction Egosoft is (and should be) focusing their attention to improve their economic system.