Really?
Then why did the new trilogy start with an Empire-successor as the dominant power and the Rebellion being a rebellion again?
Edit: Serious question, I didn't read up on any material of the Disney version between the end of the old movies and the start of the new.
The First Order is a secret Imperial Remnant hanging out in the outer Rim. It's just that with the first shot of their Nostril of Palpatine, they blew up the entire new Republic and all it's fleets, because apparently they all have the habit of hanging out near the same place. And they didn't even pick a plot important planet like Coruscant, so they had no defense at being blown up at once.
Anyway, the basic timeline goes like this
1) Death Star II gets blown up
2) The Imperial falls apart in civil war, Rebellion makes massive gains
3) The New Republic is formed, while the Empire spits out dozens of mini-states. The Confederacy comes back, as do the corporate states
4) The Imperial Remnants are defeated decisively at the battle of Jakku. A peace treaty sees the Imperial remnants withdraw to the outer Rim [interestingly that they go to the outer rim, which is traditionally the region that the Empire controlled least. It seems that Star Wars has a thing with always having their invading forces come from the Rim, and never from the center. When the CIS attacks, they do so from the Rim. When the rebels attack, they do so from the Rim. When the First order attacks, they do so from the Rim. When the final order attacks, they do so from an even rimmier rimworld. ]
5) Mon Motha promptly disarms the New Republic, cutting it's military sharply
6) The centrists (who prefer a strong, centralized imperial style government) throw a fit, and the system gets stuck in perpetual gridlock
7) The First Order emerges and eats all non-republic states , and regularly raids Republic territory
8) The Senate orders the New Republic military to avoid engaging the enemy at all costs, doing only defensive patrol. The military wisely ignores this order and cladestinly supports Leia's new rebellion
9) The First Order fires their superweapon, destroying the entire New Republic fleet and senate in one fell blow