I actually like this (not with this low of wealth value), but in how much the funds of a city fluctuates with the caravans. When the devs were talking about things they wanted in implement into Bannerlord, they brought up one being war through merchantilism, bankrupting the opposing factions to weaken them. If this is tweaked a little to allow fluctuations from, maybe 10k to 50k, I think it would work well. Add in ways to monopolize or restrict certain trade items and commodities, and it will add another level of strategy to the game!