Quoted By:
When you really think about it, these 2 are the most influential starter Pokémon in the series. Charizard is pretty much the second most popular Pokémon of all time, to the point that the versions of the games where he appears on the box vastly outsell their counterparts. Gamefreak realized they'll never have another starter Pokémon as popular as Charizard so they have been trying to recapture Blaziken's popularity since he's the second most popular starter, which is difficult seeing as they don't know why he was so popular in the first place considering he was intentionally designed to be the least popular starter. That's why Gen 4 & 5 won't with the Fire/Fighting type combination & why Gen 6 onwards often make the final evolution of the starters bipedal & take humanoid elements on their designs.