I also feel like there was an idea than Ben tried to turn him back to the light, and they fought a furious battle over a pit of lava. We get the pit of Lava. Obi-Wan doesn’t really try to convince Anakin. Other than my allegiance is to the republic to democracy. At that point of ROTS it’s obvious Anakin has turned into Darth Vader and is lost. He believes the JEDI are evil.

His wife might have been able to reach him if his heart wasn’t closed to her. He was so convinced in his mind she was going to die he made his choice.

Somehow Luke is able to reach him, to reach the Anakin within Vader. By being a mirror and example to him of what a Jedi is.

Ben in the ROTJ novel acts as if his pride and hubris was in his mind responsible for Anakin’s fall.

That was written when Yoda was Obi-Wan’s Jedi master in the backstories and Qui-Gon didn’t exist.

I honestly think Episode III shows Anakin is beyond redemption showing what he does to Jedi Younglings. He didn’t lose his cool like with the Sandpeople/Tusken Raiders, or angry like with Dooku. it was premeditated. And Anakin is a serial killer by the point of the mustafar duel. He had murdered Tusken women and children, slaughtered like they were animals. He had murdered Dooku. He had murdered the separatists who pleaded for mercy, and the trade federation leaders. He was going to murder Padme until Obi-Wan made him let her go. And then on the death star he watches as millions are snuffed out, in the original film. Who knows how many die offscreen. Billions? He belongs in Jedi hell, not heaven. Except Lukes gift of forgiveness and mercy to him. That somehow regenerates Anakin Skywalker. in his final act out of love, he sacrifices himself to save Luke. the son who he tried to corrupt to evil, and cut off his hand.

Luke followed Obi-Wan on a damn fool idealistic crusade, to save Leia and later confront Vader in TESB. Because he thought his father was a hero, and a Jedi. Not Vader the person he wanted to kill for slaying his master. He had revenge in mind when he went to cloud city. he thought he was saving his friends. He wasn’t equipped with the essential knowledge Vader was his father. Vader revealed it and gloated. Kenobi was a liar. A certain point of view.

Lukes friend’s and a newcomer save him. Artoo fixes the Falcon.