Assuming that the Gallics are pushed back into Gallia, the Rheinland-Liberty war eventually peters out and resolves itself back into a non-violent but begrudging trade relationship, Kusari resumes recovery while eventually reopening trade with Liberty, and Bretonia manages to hold on to the New London front (as it is now) before the Gallics are pushed back.
We'll still have tradelanes and gate tech, since they're still light years ahead of our understanding, and have existed for almost 300 years previously without much change.
All mining fields existent at present will have long been exhausted, forcing more exploration for mineral resources - which means new systems while old mining systems without much else going on except for mining will probably be disconnected from the gate network (since gates are expensive to maintain).
Would we see house expansionism into the Omicrons/Taus/Omegas? If so, would there be heavy resistance from the fringe dwellers that have had a hundred years of progress? What about the Outcast and the Corsair empires? Would they start expanding into something more closely resembling houses themselves?
How would technology have progressed? Would we see a stabilization of population growth, higher standards of living all around, and increased automation in every industry? What will the weapons of the future be like, and what would ships be like?
Well, it would sorta break lore if all of a sudden another Suncrusher started blowing up systems in Sirius..
Actually.. .88 will be coming eventually.. huehahueahuhahahueahahehauheahaheahh
More seriously though, the Hypergate that the Nomads use to get from place to place, is sorta.. not working. You'd know that if you played through singleplayer.
Perhaps there just isn't one located in Sirius? (And the one that existed before, merely didn't follow from Sol. Who knows. This was left incomplete.)
Noms will be destroyed and the Order will enter the chocolate manufacturing, cardamine and artifact smuggling industries and will ally with Lawfuls as well as unlawfuls, and hunt the ZA like nomads.
BHG Core will also help Order kill ZA.
IMG will try to mine alien organisms in Omicrons, coming in conflict with Outcasts and GMG
Lolberty will legalise all contraband and will turn alien organisms into contraband.
Yoda[T] will return, as well as Igiss, Mon'star , Karlotta etc.....
Phooms will return and will start trade relations with The Order.