In my 'verse the two rival mega-corporations that are in the background will begin to shake themselves apart following the events in Empire of Dust (my current WIS), ultimately causing the collapse of a centralised spacefaring civilisation and the separation of colonies into autonomous worlds, some with spacefaring capabilities, some without. In future books (if I ever get the opportunity to write them) my protags will play out their lives in the collapsing civilisation scenario. Ultimately it was their actions in Empire that sparked off the whole thing (though it was an accident waiting to happen and if they hadn't done it someone else would have - eventually).
I'm not sure I had the meta plot in mind when I started Empire, though I did have an idea that in the long term there would be some kind of expansion, collapse and reclamation of lost colonies and without ever trying to write it down I found that the events in Empire fitted perfectly into the beginning of the collapse.
Within that meta arc I could continue writing a fairly wide variety of space opera forever.