Disagree. Bulbasaur is the best one. Charmander gives the player an awful start, while Squirtle is consistently average, and Bulbasaur makes the beginning of the game really easy, and once its usefulness wears out, you have more options to work with. Bulbasaur has access to the ridiculously overpowered Toxic/Leech Seed combination, as well.
Does this study take into account alternatives to the starters? I ask because there are many, frankly better, alternatives to Squirtle, and fewer for Bulbasaur and Charmander. Even then, Fire-type Pokémon weren't very good in generation 1, anyway, so Charmander's sadly pretty irrelevant. Squirtle's alternatives as a Water-type include Slowbro, who gets Amnesia, Starmie, who is just awesome in general, Lapras, who is also awesome, Poliwrath, who's pretty good all around, Tentacruel, who's actually really underrated, Vaporeon, who has massive amounts of HP, and Gyarados, who has extremely high attacking stats. Starmie and Slowbro in particular stand out because they are so significantly better moveset-wise than Squirtle; the former learns Psychic and Thunderbolt, in addition to the Ice and Water moves that Squirtle gets, and while Slowbro lacks Thunderbolt, it gets the hilariously overpowered Amnesia, which basically lets it do anything, ever. Bulbasaur's alternatives extend to Victreebel, Vileplume, Tangela, Parasect and Exeggutor. While you can make a case for Victreebel and Exeggutor, the other three are basically worse in every way; Parasect has no good STAB, though Spore is awesome, and its stats are bad, Tangela is just bad, and anything Vileplume can do, Venusaur can do better. You could make a case about Victreebel being a good alternative, but it lacks Leech Seed and is slower and more frail. The only awesome alternative to Venusaur is Exeggutor, and even then, the only thing, besides better stats, more than Venusaur that Exeggutor brings to the table is Psychic, which is admittedly quite helpful, but does not make as significant of a difference as Starmie getting Thunderbolt, in addition to Psychic, makes when compared to Blastoise.
TL;DR: Bulbasaur offers a good start, allowing the player to hit the ground running early-on, and gets a powerful combination of moves. It also has fewer good alternatives than Squirtle, and the better alternatives to Venusaur are less significantly better than the good alternatives to Blastoise. Even if this doesn't automatically tip the scale in Bulbasaur's favour, it's something important to think about. Charmander, on the other hand, isn't very good in generation 1, so it isn't relevant to the discussion.
