Like I said at the end . It is unsettling to be a civilian in an age where there is no incentive or strategic benefit to protecting you . Given that we have already given up on any substantial and concerted attempt to defend civilian populations from nuclear attack , I don ' t think we ' d have a particular qualm with allowing planetary losses in an interstellar context . Cities in WWII were interesting because they ended up being strategically vital not because they were population centres or fortifications , but rather because of their position as hubs for the movement of materiel . Conflicts in cities were sticky because both sides could feed the churning machines of war in transit hubs in ways they could not in the open countrysides . It had nothing to do with people or defensiveness . The patriotic defense of Stalingrad was tacked on , and did nothing to stop it from being almost entirely annihilated . In a stellar context , that stickiness is totally irrelevant . As for blockade you cannot stage significant fleets planetside . Getting large ships out of gravity is almost impossible . As a result , any kind of planet based fleet is going to be minimally armed , with poor mobility because it needs both interstellar and atmospheric engines . That is easy to keep penned up , or intercept . It does not require significant commitment , but more importantly , does not introduce a threat like an army or host of knights in a fort might . A small fleet of raiders would be better served hiding in an asteroid belt than on a planet . The point is also asymmetric it would take the production mass of millions of ships to reasonably shield a world from orbital bombardment . It would take a handful of ships to reasonably blockade such a world . A planet ' s ability to supply is not limited by its actual physical capacity , but its capacity to get that offworld and to somewhere useful . Of course they are useful , but only if their lines of supply are maintained , and they have a significant fleet that can strike from it as a base , requiring orbital facilities . In that equation , the planet is worthless without the fleet , and so the fleet is the strategic priority , not the planet . The need for extraplanetary factories is maybe better described as extraplanetary shipyards . Voidcraft fabrication of any reasonable size requires it be made offplanet or gravity makes it impossible . Sure you can manufacture the parts planetside , and ship them into orbit for assembly , but at that point , it makes more sense to integrate asteroid mining with all elements of fabrication and assembly and avoid the extra cost of planetary transit . They are less defensible , but nothing is defensible , so the efficiency matters more . No , if planetary shields were even remotely powerful that would be the case . But as it stands they add at most a week to a siege , making it functionally undefended . Or if Stellaris accurately modeled supply lines instead of making all your minerals magically available in every corner of your empire it would cease to be useful under blockade . The relevance of planets in Stellaris is only in terms of their postwar ability to produce and project . At the point that I have destroyed the enemy ' s ability to wage war , I have won . That ' s not planets , it ' s Spaceports .