In MMOs (and paradox games) there is money (pounds, ducats, gold ...) for the maintenance of the army. If you arrive at 0 and you are in negative balance, the troops start to have low morale until they desert (ck2) or you start to make debts on debts until you go to the broken bank (victoria 2, EU4) and have heavy penalties if you go bankrupt . On eu4 there is a unit limit (land and sea) if you exceed it the excess troops cost double or triple upkeep if I remember correctly that to add up to the normal upkeep. Normally for merchant ships it is done because if you earn 100, at the cost of 50 ship maintenance, it is worth the penalty to have more bonuses ... On stellaris I don't remember (I don't play from the super armio patch from the megacorp one, I don't remember ), but if I am not mistaken if you go in defcit of energy credits you have malus to the army (and if you run out of food the population starts to drop, except if you are robots). So in all, I repeat ALL paradox games there is active maintenance. I don't know why paradox removed a lot of things that could have been at D1 in the game that created imbalances in the game. It can be understood from a new company ... but not from an experienced company like the paradox ...