Here's why:
* Shiny forms are permanent: A Pokémon's shiny status is determined when it's created. It's a fixed characteristic, just like its species, gender, and IVs.
* No in-game mechanics exist: There is no mechanic in any Pokémon game that allows you to change a Pokémon's shiny status.
* Breeding: While breeding a shiny with a non-shiny Pokémon increases the chances of getting a shiny offspring, it doesn't change the original shiny Pokémon's status.
So, once you have a shiny Pokémon, you keep it that way! 😊