>>53153706Lorewise? Bulbasaur didn't want to evolve and Ash respects his Pokemon enough to evolve if they truly wanted to.
Animation reason? I guess Bulbasaur is easier to animate?
Shilling? Everyone loved Charizard during Gen 1, seeing Ash get a Charizard and it later listening to him made lots of 90's kids excited. Nobody gave a shit about Venusaur back then. Ironically it's the opposite now, people are getting tired of Charizard pandering and want the other Kanto starters to get some love.