Right, but will Fleet Carries have mission boards? Contacts? material traders? Factions? One would need those things to have a civilization, no?
No. Most people probably dont take missions.. dont care about factions and as for contacts (like material traders and others) - the ships might have some assortment of contacts for those non-faction specific station services that depend on the type of carrier you get or equip.
All you need for what most people do in the game is a place to sell the crap you mine or buy or explore and a place to buy some of those things and ships and their parts. Add in the existence of other people as a bonus and you have most of what you need.
Really the only downside will be the lack of npcs in non-inhabited systems since those spawn when any real station exists in a system. That'll just make mining and exploring much more lucrative though since there will be a 0% chance of having to deal with interdictions or anything else like that. Unless the npcs get spawned.
there will be good reason to overlook some of the downsides since players will be able to build lore around their bubbles and that'll be fun in of itself. Not being beholdant to the whims of the narrative to dictate how humanity uses the galaxy.