I have detected a possible system loop that could be used by players to make more money. I am not encouraging anyone to exploit it, I am just warning the devs.
Basically, the loop is the Baseball League. I recently re-created my nation and I found out that the baseball team (its name, but most importantly its upgrades) stay the same.
The reason I see it as a loop is that one player can invest as much money in the upgrades, re-create a nation, and with the free money from the tutorial, re-upgrade it and so on. With enough upgrades, a player could make much more money with the stadium upgrades and win matches with the baseball player upgrades.