what if wee see ash's bulbasaur come back from oak's lab, that way ash has a grass type and a poison type which he can use against the fairy type gym and we can see it be fully evolved by the league or be in its middle stage and evolve during the league and we see somebody give ash a keystone and megaton so he can mega evolve his venasaur
Why can't he simply catch a Kalos Grass-type instead of using a Grass-type who peaked more than a decade ago?