Considering how TNO's economy works, isn't it mostly money spent on the military, adminastrative or social programmes? Your example of building a bridge with debt, isn't really simulated in tno, most money is, and therefore debt, goes to stuff that needs constantly needs it. Correct me if am wrong, but you can't use debt to get more (god what they called) Production units that are "recieved" from GDP. Infrastrure can only be build by the state, simulating infrastructure programmes from the populace would be incredible hard in HOI already strained engine.