No, seriously, why do they? It’s not like the construction workers don’t get paid their wages if they aren’t given such projects, and, unless you are buying the resources from overseas, the only cost for the construction materials for the state is wages/salaries of the workers who are involved in the relevant processes.
Am I being swindled?
Yes, you basically play as a city state. The whole premise of the game is that you are developing an independent 24x24 km square republic with no modern industry. Maybe that’s not realistic, but neither are a bunch of other things in the game.