The prequels may have sucked, but as with the original trilogy, they had tons of throwaway lines and slivers of worldbuilding that formed the basis of countless other stories set in the era. Like, remember that dorky line from kid Anakin about padme looking like an angel from the moons of Iego? People rolled their eyes when they heard it in theaters, but then Filioni and co. made a whole episode of the Clone Wars TV show where they actually went to one of those moons, and we actually saw one of those "Angels." And this was just in the context of a larger plot that played out over two episodes and tied into the planet of Naboo.
The sequel trilogy, in contrast, gave other creators practically nothing to work with. Instead of countless little tibits of lore that could be expanded upon, JJ and co gave other creators massive gaping holes. And yet, simultaneously, the removal of tiers of canon AND the insistence on the movies taking priority, meant that nothing in all the comics, books, and TV shows matters in the end, because the only times the comics are allowed to fill those holes is if the movies don't intend to. So, the Knights of Ren finally have a backstory, because neither JJ or Rian were willing to provide it? Who cares, cause they sat their asses and did nothing over the course of the trilogy apart from being killed off in all of 30 seconds.
And in contrast: "so Rey finally has an answer to her who her parents are as of the Last Jedi. Maybe we can explore more what that means for her as a character and... wait, you want us to ignore what Rian set up so JJ can make the Emperor her grandfather? I guess she'll just have to have some entirely inconsequential adventures with the rest of the core cast."
(I have no idea if that conversation actually happened, but it's telling that, looking over wookiepedia, what Rey canonical did between TLJ and TROS is very scant and sounds thoroughly uninteresting.)
And even if some of this shit WASN'T mandated (like there being no tiers of canon), JJ's disastrous final movie killed what little interest people might have had in this era. It's all about The Mandalorian now, plus Clone Wars returning. Speaking of which: I saw a youtube video recently that argued that, due to Clone Wars TV show already having jumped back and forth across the timeline during its original run, there's no reason that Disney can't greenlight more episodes that take place before the 4 part finale.
And George always said they had enough material for 10 seasons, and the wiki entry on canceled episodes seems to collaborate this, cause it's rather long. I'd be far more interested in seeing some of these stories realized on-screen than ever spending anymore time with Rey, Fin or Poe. And if enough people agree.... well, there's money to be made, and there's nothing Disney loves more than the almighty dollar.
