Here's why:
* These Pokémon are from later generations: Mew, Deoxys, Jirachi, Lugia, and Ho-Oh were introduced in Pokémon Gold, Silver, Crystal, and later generations. FireRed is based on the original Red and Blue versions, which do not have these Pokémon.
How to get some of these Pokémon in other games:
* Mew: You can obtain Mew in the original games through a special event or by transferring it from a later generation game.
* Lugia and Ho-Oh: These are legendary birds found in Pokémon Gold, Silver, and Crystal. You can transfer them to later games.
* Deoxys and Jirachi: Deoxys and Jirachi were introduced in later generations and can be obtained through various events or by transferring them from compatible games.
Important Note: You cannot obtain these Pokémon in Pokémon FireRed. You'll need to play a later generation game or use a special event to get them.