>>45993387You don't even have to look at the full dex, just look at the main mascot, Pikachu.
His design went from chunky electrical mouse with small limbs and a longer, skinnier tail to having much longer limbs, a more pronounced face and being skinner/longer.
Being the face of a franchise doesnt help, but pokemon sells SO much merchandise that obviously they are going to change the design of the monsters themselves to sell said merch.
