survivors have a terror radius to react to while killers have nothing. not being able to find a survivor for the first couple minutes of the match is vastly more crippling than not being able to see the killer at all times (although this can still help the killer out in some ways). while you are right that the killer can’t be everywhere at once, gens on rpd take way too much time to reach. if you hear a gen being worked on upstairs, you have to locate a staircase, make your way upstairs, go to the gen the survivor is working on, catch up to them since they’ve most likely began running early, and hold w through linear corridors until you’ve eventually downed the survivor. this is ample time for multiple other gens to be completed and the inability to quickly switch targets quickly forces you to commit to long chases.