Silly man, Anakin was destined to destroy the dark side from the beginning. The Chosen one as prophesied. The theft of his whole life, his son and daughter, his wife, his mother everything, all of it was meant to hammer and twist him into something dark enough to get close to the emperor without being broken beyond repeair. Luke was a pawn of this destiny. Luke could never have destroyed Palpatine and did not, he was simply the trigger to pull Anakin out from where he was hidden under the name of Vader as the weapon of the light side. It was only Luke's suffering that was a mild shadow of his father's and then the splaying out of that suffering before him that allowed Anakin to execute the final task that was the prophesied culmination of his life of anguish and destroy the Emperor.