Kanto: based on Kanto
Kanto Starters: Got Megas in Gen VI, Gigas and insanely buffed movepools in Gen VIII.
Venusaur: Consistently one of the best Pokemon in the game
Charizard: Is Charizard
Blastoise: Shell Smash, Fake Out, Life Dew, Aura Sphere, etc: Even without optimized stats, its movepool is wide enough for it to always have a use.

Johto: based on Kansai
Johto starters: get no significant buff in nearly 2 decades. Were removed from the main series in the only generation where they could have gotten the moves they need to become usable.
Meganium: A support mon with next to no support moves. Based on a flower but no powder moves except for PoisonPowder which is just a worthless version of Toxic. Is the worst starter in the franchise
Typhlosion: A special attacker with only one type of Special Attack. Based on a Volcano but no Earth Power or Ancient Power. The only Pokémon in history where "Do not ever use this Pokemon with the intent of winning games" is unironically used to describe it
Feraligatr: The only Johto starter that isn’t a shitmon but is still worse Gyarados due to its awkward stat spread and comparatively poor coverage.

Masada: "Laughs"