I believe that is a false assumption. A decentralized gold system encourages participation. Assuming lords guilty until proven innocent is an incorrect attitude.
What is wrong with margraves asking for funding? Too proud? Dukes can get enough with taxes.
I don't think we're ever going to get to a point with changing culture in BattleMaster where people do not assume that being the Lord of a city will grant them—and, indeed, entitles them to—a higher income than they would get in a rural region.