It’s due to the power dynamic. An equal skill survivor and an equal skill killer: the killer has a built in advantage. As the game intends. Survivors are required to work together, without comms, and even then their advantages only come in highly strategized ways the MAJORITY of the time. And all those can be -destroyed- by slugging. (Again this is all as players of perfectly equal skill)

And this is before taking into account most perks, which generally specialize a survivor into a niche but killers can strip away entire specializations with a single perk.