>>55671030Even a full-ingredient Gengar can only get ingredients about 30% of the time. All species are unique, so there are also berry or skill focused pokemon that actually have higher rates of picking up ingredients compared to ingredient types. Of course the non-ingredient types are still going to be worse at it since they pick up half the amount.
A lot of it has to do with game balance, since the quality of ingredients, and the speed of how fast each pokemon works is pretty balanced.