Why isn't Ganon gone after I defeat him? [duplicate]
Solution 1:
When you finish the game your save profile will display a star to show that you've defeated Ganon. When you load into the game again it will load back into a state where he is alive - this is intentional. The allows you to play the fight again using different weapons and fighting styles.
After Ganon is defeated Kilton will have new dialog when spoken to and Symin will sell photos for your compendium. Additionally, your save game will now display a percentage to track the completion rate of the game for players who want to reach 100% completion of every activity.
In short, you cannot play in the open world where Ganon is dead. He will always respawn.