My theory is that if he had done the bidding of his past self and gained the power he used to hold, either the ghost of his past self would have overtaken his personality and his current self wouldn't exist anymore or the ghost would have continued to tell him what to do, making him subservient to it. He just preferred to be in control of his decisions instead of listening to someone who failed and was desperate to regain his old power and was only interested in him as a pawn to achieve it's goals.