The problem is you have a royal duke who does not appoint lords in his duchy. These regions have no steward. You want access to the region's food. Correct?
Why is the problem with the last part rather than solving the cause? Can you think of any other more common circumstances that would demand a similar change?
That's probably a better way of putting it: if it were easy to control the output of a region with no Lord, then what incentive is there to appoint a Lord in the first place?
