What makes a good starter trio?

I've been thinking about it and I don't think there has been a trio as good as the original 3. It's the only time all three were good Pokemon. Charizard is completely fine and gives you an easy Fly. Blastoise gives you an easy Surf while being really good. Venosaur has nothing but it dominates in power.

Every other gen one of the starters, usually grass, is shit. One is fine and one is overpowered. I love Chikorita but she's shit. I love Treeco but... come on. It's shit. Torchip is fine but Swampert is so much more powerful it turns the whole thing into a joke.

The philosophy seems to be that it's a difficulty slider but that's dumb as fuck since after 2 gyms, the starter no longer defines how hard the game is. It's just an emotional support Pokemon. A mascot for the player. Gen 1 made all 3 powerful so all players were satisfied. The difficulty slider thing was a myth made by Charizard fanboys to convince themselves they're hardcore. Charizard was objectively the worst one so the difficulty thing makes no sense.

Starter trios should always be the cornerstone of your team. Thus they must be the most powerful Pokemon you can have except for some endgame Pokemon. They should not be a difficulty slider based on how shit your Pokemon is but based on their playstyle. One for offense, one for defense and one for, I don't know, playmaking or some shit.

Only Gen 1 ever got the trio right and every trio after was handicapped by Game Freak playing favorites.