Harry Potter didn't 'save the world' at the end of the series, and the last sentence of the book is proof

• At the end of "Harry Potter," the titular hero didn't save the Wizarding World from all its evils.
• Harry's last thought before the series' epilogue is if a house-elf will make him a sandwich.
• Wizard supremacy appears to be alive and well 19 years after the Battle of Hogwarts.

Harry Potter is lauded as the brave and successful hero of his titular fantasy series, but what actually changed after he defeated Voldemort?