So after ROJ, rather than putting the screws to the remnants of the Empire, all the forces in the galaxy just said 'fuck it - it's not like they're going to re-gather, built more advanced ships, train more troops and build another larger super weapon…'
If our OT heroes couldn't stabilize the galaxy in 30 years, what hope does the new batch have? There's no reason to believe they have greater skills and that the galaxy at large even gives a shit. If they did, they would have fixed things when they had the chance.