That's just my feeling, and I certainly would love to be proven wrong. I am just a bit biased, after all.
Even if GX had survived, its culture would have become pretty much unrecognisable within six months of Selenia going (as she inevitably would one day). All it takes is for the driving force of any given culture or atmosphere to disappear and within half a year most nobles in the realm won't even remember it, let alone follow it.
(Which is why the constant cycle of destruction and rebirth is a good thing in the game).
