But if we assume that the sequels were made when they were, during the last decade, then an EU adaptation still could have worked, although some fans would certainly not approve. See, TFA came out in 2015, 32 years after RotJ. In the old EU timeline, that would put it approximately around the time of the New Jedi Order series, give or take a few years. And that was probably one of the more infamous series in the EU, introducing the Yuuzhan Vong, dropping a moon on Chewbacca, and generally taking a darker turn than most fans were used to. A movie adaptation of the series would also be somewhat difficult considering how many novels it spans.
So yeah, it was possible, but Disney chucked the EU out the window and gave us memberberry-infused deconstructionist retreads of the OT instead. With what we got, I think I'd rather have the weird biotech aliens.