Cities need a great deal more gold for infrastructure than other regions,
This is indeed structural in the way the game is designed.
and their lords are also most often the sponsors of armies. They also tend to be the people the realm comes to when nobles need extra gold handed out for their units.
These, however, are cultural remnants from the time when Dukes were the City Lords and food was basically free with the ox cart system. The system has changed and the people can change too.
