Isn’t that a TFA issue? Several of the inconsistencies and “plot holes” listed here apply to TFA too.
To an extend, but at least in TFA there was still a New Republic, and the barren conditions of the FO’s home base made it seem like they were a well supported fringe government, run by extremists. Given what happened in TFA, I would have expected both the New Republic and the FO to be severely weakened. This should have given rise to a totally different dynamic in the conflict, with two nations fighting a war of attrition with limited resources. However, it was not to be. The New Republic was destroyed, and the FO seemingly unstoppable without explanation.