what is a legacy? it's planting seeds in a garden you never get to see.
With The Rise of Skywalker touching on the Force Spirits (Force Ghosts), it’s interesting to go back over what we do and don’t know about them, which is both more and less than we might expect. What it takes to become a Force Spirit is that you must be selfless and compassionate (which are the things of the light side, it’s basically impossible for dark siders to become a Force Spirit unless they give up the dark and do something significant that’s entirely selfless) and special training to be able to do it. Jedi don’t automatically become Force Spirits, Qui-Gon Jinn had years of training and couldn’t complete it before his death, so he could only appear as a disembodied voice to Yoda. He does briefly appear on the planet Mortis, where he describes the place as, “Unlike any other [place], [it is] a conduit through which the entire Force of the universe flows. This planet is both an amplifier and a magnet.” We don’t know for sure this is the actual Qui-Gon Jinn (though, I tend to think it was), but we do know that his voice is able to speak to Yoda towards the end of the Clone War, telling him to go to Dagobah, which is “one of the purest planets” in the Force. Yoda later tells Anakin of this encounter, planting the seeds for the future acceptance (Dave Filoni and Leeland Chee confirmed that this conversation is what helped Anakin later), as well as Pablo Hidalgo once tweeted re: how Anakin became a Force Spirit was, “It’s been overheard that George said he had help.”, which implies that Obi-Wan and Yoda helped him at the last minute. The reference to Mortis and Dagobah being incredibly strong in the Force as planets is important, because I think that this is precisely what Ahch-To is as well (given that this is where the Jedi started, it makes sense that it would have been a place strong in the Force, enough to awaken that part of them), hence why Force Spirits can appear there and do things on that planet that I’m not convinced they could do elsewhere. It’s the only place where we’ve seen the Force Spirits do these things. There’s a lot more involved in all this, like the Force Priestesses are the ones who taught Qui-Gon and Yoda directly, Yoda tells Obi-Wan during Revenge of the Sith that he’ll teach him how to commune with Qui-Gon, which implies that Qui-Gon then taught him, we see the process of Obi-Wan become a Force Spirit in Time of Death (it’s a painful process that flashes over instances of the moment of his death and the various moments of his life, until he finally gathers himself back up), etc. But the really interesting part is how the canon has also shown us this is not an easy process just to hear their voices in the first place. Obi-Wan can speak to Luke a short while after his death, during the trench run on the Death Star, but it’s not until three years later that he appears visually, which is during a moment when Luke is getting closer and closer to the border between life and death. How much of that is Obi-Wan learning the process of appearing and how much is Luke learning the process of being able to hear? It’s unclear. During the ending scene of Return of the Jedi, we see that Obi-Wan, Yoda, and Anakin have all become Force Spirits and Luke can see them now–but, when Leia comes up next to him, she doesn’t seem to see them at all, to realize what Luke is looking at. This is after the reveal that she’s Luke’s twin sister, after all the hints of her being Force-sensitive, we know she has the capability, yet she still doesn’t see them? Take it with context, though–Yoda specifically has to teach Obi-Wan how to hear Qui-Gon’s voice, not just Qui-Gon showing up and saying hi. Even more clearly, in the Ahsoka novel, Obi-Wan struggles intensely with this process of learning to hear the Force Spirit:
This is a very long, very difficult process, just to hear them. There’s a lot of corners that can be cut when you bring extremely powerful Force-wielders into the equation, like Anakin probably straight up cheat-coded his way into becoming a Force Spirit (with Obi-Wan and Yoda’s help) because he was the Chosen One, and the book Legends of Luke Skywalker (in as much as you can take it as canon, as it’s stories within the story) implies that Luke “argued” (he says with a smile, indicating fondness) with his teachers for years after their deaths, showing that they could have taught him, as well as in The Last Jedi novelization, Luke hears a voice saying, “Let go, Luke.” and maybe it’s one of them, maybe it’s the Force, but it would fit if it was Obi-Wan, Yoda, or Anakin helping him over. This can then be applied to both Leia and Ben as well, that they may not have needed the same formal training, because they’re descended from the Chosen One himself (aka, the Force literally runs in their veins) and because I absolutely would believe they were all cheat-moding each other after death, something that’s only possible because they’re Skywalkers. All of this answers two important questions about The Rise of Skywalker: Why does Rey have such trouble getting through to the Force Spirits? Why did the Force Spirits never appear to Ben Solo? Because it’s hard to hear them, not just hard for the spirits to appear. Rey had to practically be at the border between life and death herself to be able to hear them, it seems pretty consistent with what we saw of Obi-Wan’s difficulties, he literally had to “break through the wall of life and death” to hear Qui-Gon’s voice. Luke was treading that same line on Hoth when he finally saw Obi-Wan’s spirit. Once you learn how to do it, it becomes easier, you can see them without having to get back to that place, but that’s why Rey has so much trouble connecting with them, even when she’s been trying for so long. And why don’t they appear to Ben Solo? We’ve seen nothing of him training for this (possibly he might have when he was younger with Luke, while he was training to be a Jedi, but we haven’t seen anything of that yet, as well as he didn’t know Anakin Skywalker was Darth Vader until at least mid-20s or so, which makes me doubt how much Luke or Leia would have let him have contact with Anakin’s Force Spirit), but more importantly: We see in The Force Awakens, Ben was trying to reach the spirit of Darth Vader, not of Anakin Skywalker. He’s trying to commune with Vader’s mask, of course he’s not going to hear Anakin trying to reach back to him. If he’s not even trying to reach the real Force Spirits, they can’t just pop in unless he really focuses on hearing and seeing them. That’s part of why their lack of appearance fits for me in the movie, because Force Spirits popping up out of nowhere only happens when you’ve already learned how to commune with them. And that process is hard as hell on both sides.