But if Harry is a Horcrux, there will always be a chance for he who must not be named ti return!!
Maybe Hermione figures out a way to rid Harry of being a Horcrux at the cost of Harry losing his powers. Though without his magic, Harry is still an excellent Seeker and goes professional, becoming the Wizrding worlds best Seeker ever without any magical powers. That would still make Harry happy and still keep him in the Magical community.