Your cup is still full. You can influence the galaxy (your own private galaxy) offline, but the development and richness that will happen because of the background simulation, the influence of the actions of many players and injected events will of course not be available. But I would consider these as extras not as losses if I were planning to play single play offline.
If that is the case i am good with it, but as you read in some previous posts now we might even not get background simulation, i am ok with the galaxy not evolving because of some players actions or some dev injected events since i will be playing in offline, but if the team decides to cut some single player events,features just to force me to be online, now that i cannot take.
Even if the full background simulation was running (which it sounds like it won't), the changes that a single player can make on a 100 billion star galaxy will be almost immeasurably small.
Its ok i am good with that, i want my own galaxy, but events can be made if they actually program the npc to attack space stations and stuff like that kinda like crusader kings 2, everything happens around you even if you don't do anything, 1 faction can rule the world and you can still have 1 country (i know they are 2 tottaly different games but still)