One of the biggest criticisms of Rian Johnson's Star Wars: The Last Jedi is that he retconned J.J. Abrams' The Force Awakens, but that's not what happened. Abrams brought the Skywalker saga roaring back to life in 2015 with The Force Awakens, which featured the old heroes alongside new characters on a new adventure. While sticking close to the blueprint of the original Star Wars, it was nonetheless a thrilling start for Disney's sequel trilogy.
Fast-forward to 2017, and things took a turn for the worse when The Last Jedi was released. The most divisive Star Wars ever made, The Last Jedi broke the fandom, with disagreements over all of its decisions: from killing Snoke to its treatment of Luke, the reveal of Rey's parentage and its use of humor, fans either thought it was one of the best in the franchise or one of the worst. The vocal response factored into Disney's strategy going forward, especially with Abrams returning to direct Star Wars: The Rise of Skywalker.
The final installment in the Skywalker saga, The Rise of Skywalker retconned The Last Jedi, but that's ostensibly just what that movie did to The Force Awakens, at least according to its critics. That was and remains a major talking point surrounding the middle chapter of the sequel trilogy, but for all The Last Jedi did go in some unexpected directions, it didn't directly retcon or change anything from The Force Awakens.
Snoke Wasn't Anybody In The Force Awakens
One of Star Wars: The Last Jedi's most controversial decisions was the death of Supreme Leader Snoke at the hands of his apprentice, Kylo Ren. While a dark side student killing off their master isn't out of the ordinary for Star Wars, the timing of this move was certainly shocking. Snoke was seemingly the Big Bad of Disney's sequel trilogy, and so having him die before the third act of the second movie was wholly unexpected. What's more, though, is that The Last Jedi didn't explain anything about Snoke: who he was, where he came from, how he rose to power in the First Order.
It's true that The Last Jedi ignored those questions, but it's equally true that so too did The Force Awakens. J.J. Abrams introduced Snoke as a shadowy figure, deliberately mysterious, with absolutely no hints of his past. He wasn't so much a character as he was a mystery box; one that Johnson took and drove a lightsaber through. But it stands to reason that The Last Jedi made the more interesting choice regarding the Supreme Leader.
There was little time in an already packed movie to delve into Snoke's origins. The character is of the archetype fans had already seen, a Palpatine redux (and, as later revealed, actually a Palpatine puppet), and killing him off not only made for a stunning plot twist, but it passed power on to the far more interesting and complex villain of this story, Kylo Ren. Had Abrams given more overt clues to there being something actually important about Snoke's backstory, anything to suggest that would factor into the story, then it might have been a different matter. He didn't, though, and The Last Jedi made a stronger choice by killing him off, without going against anything in The Force Awakens (because, really, there was nothing to go against).
Rey Was A No One Before Last Jedi
Another common complaint of Star Wars: The Last Jedi is that it dropped all of the setup regarding Rey's parentage from The Force Awakens, instead choosing to make Rey a nobody. Like with Snoke, this came after two years of theorizing as to who Rey really was: a Skywalker or a Solo? A Kenobi or a Palpatine? Although The Rise of Skywalker has since changed the answer to be that Rey is the granddaughter of Palpatine, in turn twisting Kylo Ren's words in The Last Jedi, Rian Johnson decided to reveal that Rey's parents were nobodies.
Because of the theories and apparent setup, this was another element seen as a deliberate retcon of The Force Awakens. But in that movie, Rey is absolutely a no one. She's alone on a junkyard desert planet. She longs for a family returning to her, but clearly doesn't really know who they are. She's told the belonging she seeks is not behind her, but ahead. It was always unlikely she'd be a Solo, given Han didn't recognize her at all. Neither Obi-Wan Kenobi nor Emperor Palpatine were truly hinted at, though clues can be retroactively applied (like the voices in her Forceback vision). And her being a Skywalker was surely too obvious.
As well as that, the point remained that, for all intents and purposes, heading into The Last Jedi Rey's parents were still unknown. And so Johnson simply kept it that way, but actually gave an answer that had depth and meaning, that challenged Rey's entire sense of self and made her all the stronger for it.
The Knights of Ren Weren't An Active Part of the Story
Star Wars: The Force Awakens didn't just introduce Kylo Ren, but also a mysterious group known as the Knights of Ren, with Kylo referred to as their "master". Aside from that one brief line from Snoke, the Knights of Ren's only appearance was in Rey's Forceback vision, where Kylo and the Knights stood, weapons drawn, on a rain-soaked planet. It was unclear whether this was the past, the future, or something that may or may not ever happen at all, but it was an intriguing tease all the same. But that's all it was, a tease.
The Knights of Ren then didn't appear at all in The Last Jedi, which was seen as dropping yet another plot point from The Force Awakens. But the Knights of Ren didn't need to appear, because they weren't with Kylo Ren at the beginning of the story. Given The Last Jedi picks up right after The Force Awakens, then it wouldn't have made all that much sense for the Knights to suddenly be there. Abrams brought them back for The Rise of Skywalker - and didn't do a great deal with them again - but if he'd wanted them to be in The Last Jedi, then they should've actually been around in the present day of the story. The Knights of Ren weren't actively involved in the conflict when Johnson took over, and so there was no reason to include them at all.
Last Jedi Didn't Have Many Options For Luke Skywalker
Of all the perceived problems with Star Wars: The Last Jedi, perhaps none are as controversial as what it does with the saga's greatest hero, Luke Skywalker. The daring Jedi of the original trilogy is gone, replaced by a lonely old hermit who has cut himself off from the Force. Even Mark Hamill strongly disagreed with The Last Jedi's Luke, and it's yet one more element that was seen as going against Abrams' plans. But therein lies the problem, because yet again there was little actually done with Luke in The Force Awakens. Like with Rey, Snoke, and the Knights of Ren, it wasn't a retcon because there wasn't much to actually change.
It was The Force Awakens, after all, that made the decision to have Luke isolated on an island that was almost impossible to find. To not have him return when his own sister desperately needed his help, or when his best friend was murdered by his nephew - all things that, were Luke connected to the Force and still the same Luke of old, he'd have done in a heartbeat. Johnson picked up the reins with a Luke Skywalker who was stranded on an island, confronted with a mysterious young girl he clearly wasn't delighted to see, and who had turned his back on the Resistance, on Leia and Han, and being a hero. The Last Jedi, again, gave that a story, meaning, and depth, and brought things full circle by ending with Luke Skywalker as the hero and hope of the galaxy once again. The Last Jedi didn't do away with the old Luke; The Force Awakens had already done that. Instead, it's the movie that brought him back.
The Last Jedi's Story Continued The Force Awakens
Star Wars: The Last Jedi's story picks up where The Force Awakens' left off, and although it goes in some directions people perhaps didn't expect, there's nothing on a story level that goes against what The Force Awakens had setup. Rey, now on Ahch-To, trains in the ways of the Force with Luke, tapping into her potential and becoming stronger than ever before - and on the cusp of being a real Jedi by the end. Kylo Ren continues his own development too, once again displaying the same inner-conflict he had in The Force Awakens, and once again doing what he can to push that away, becoming both more torn apart and more of a villain.
Characters like Poe Dameron, Finn, and Leia continue to fight, each challenged in their own ways; the battle between the Resistance and the First Order rages on, becoming ever more desperate for the ragtag group of survivors, and leaving Abrams with a wealth of possibilities for Star Wars 9. Not only does The Last Jedi not retcon The Force Awakens, but it develops and improves all of its core elements too.