Zombies On The Move
Not everyone's a zombie slayer. Else where would be the fun in that? The whole world'd be wiped clean and then people would have to find whole new occupations because there are no more walking dead with rotting tongues and disgorged bowels walking about scaring the crap out of little old ladies and making children drop their lollipops.
Not everyone's a zombie slayer.
Kind of for the same reason why you can't use a silver dipped wooden stake to kill a zombie. Zombies are not werewolves and certainly are not vampires. Although, zombies are more like and werewolves do not exist. Can't say the same for vampires. Thos nasty buggers just pop up everywhere. So, one could be a vampire-slayer, but Buffy made that overdone so most of the vampire slayers are out of business because Hollywood's ruined them; zombies are a safer bet.
Not everyone's a zombie slayer for the same reason that not everyone can see Big Foot. Afterall, Sasquatch knows his woods and he knows his way about and how to avoid cameras; he's seen what happened to Nessie. He just wants peace. And zombies aren't so careful, they can't help but make noise because they're always hungry: much easier to catch, I say. So, it wouldn't make sense to be a Sasquatch-slayer because there's only one and that's just being selfish to all the other Sasquatch-slayers out there too.
Not everyone can be a zombie slayer for the same reason that we can't all be ghost hunters. Sometimes, we scare the ghosts more than they scare us. You ever wonder why a ghost just keeps repeating the same old tune : 'GET OUUUUUUUUUUT!!!!' So being a ghost hunter is more annoying to the ghosts than being a zombie slayer is to the zombies. At least zombies can't talk.
So, for the same reason that everyone cannot be a zombie slayer--after all, it's a dangerous and lonely existence and you'd be too worried about a class-4 outbreak that could sweep the globe and whether or not you should have gotten those cans of beans or maybe the other shinier looking ones at Lowe's, whether or not Cananda's your best bet or a lonely island out in the middle of Pacific Nowhere, whether or not the zombies'll be walking for ten years or twenty or is humanity extinct altogether and you're the last one alive to talk about what it was like to be human on a lonely rock of an island with Fido as your only comapnion and he's looking at you like your a t-bone steak--not everyone can be perfect in relationships. You have your highs and your lows, but you gotta roll with the punches and sometimes, just let shit flow.