i would like to quickly address a few things mentioned in the comments above.
1: it doesn't matter if the AI can take a planet from you or not in this context. the AI's capability to defeat the player is not what i am addressing, i know especially atm the Ai is broken.
not the mention this game also contains something called multiplayer.
2: you don't always have a backup planet specialized in whatever you just lost. espcially early game or when you are going tall, you know...
when you don't have 100 planets.
3: i understand that a system where risk is rewarded by specializing your planets, is a good thing. a thank you to the comments reminding me of that (not sarcastic).
but the penalties to failing to maintain one of these planets can be far greater than i think you guys realise.
now yes you can use the market to stay afloat. but i am sure there can be situations, especially in the short term, where you may not have enough income in other areas to be able to afford buying your defecit from the market.
i'd like to give an example from HOI4. you can choose dispersed or centralized industry, the one produces more while the other is better protected from air attacks and also can adjust to new production lines faster. this is a system where you can specialize your production, but are less maneuverable. this is a problem when for example you need to build new types of tanks or update the guns. and ofcourse also when the enemy has bombers over your country. but your production isn't completely crippled if you choose specialized and something goes wrong.
in stellaris however, lets say you are caught off guard or made a tactical error and you lost but in the next war you should still have a fighting chance. but you do lose the only forge world you have. you will barely be able to pay the ship upkeep from the forge on earth let alone pay the alloy to rebuild the fleet you assumingly lost in the war. and you can't just buy alloy because 1 alloy costs at least 16 EC and you cant afford 50k EC to rebuild that fleet, and you likely won't have until it is 10 years later and the second war is declared to have taken more territory from you, this time you were prepared but your economy did not have the time to prepare.
you are a sitting duck for way longer than you should be. and after losing that forge world it is unlikely you will survive to see a new one under your control.
now yes i understand HOI4 isnt stellaris and the system used there isn't as simple but it is a good example of what i mean.
it is especially a problem for AI because ai is already bad at building it's empire, let alone know what to deconstruct in it's empire.
from my perspective the deconstructing/replacing part is especially a problem for the AI because i see this happen in other games too.
i would be less concerned about this issue if the AI didn't bother at all with specialisation, but from what i understand they do bother with it.
4:
@Todie please before you post read what you wrote and correct the obvious typos at least once because what you wrote is barely understandable.