Is there ever an apocalyptic movie/show where people actually, you know, band together rather than killing each other off? Seems to me if you were down to a handful of human survivors, you might want to do your best to actually keep them alive. You know, so the race can continue. But in every one of them, any time two groups meet, BLAM, gotta kill 'em! As few people that are seen in this show, I can't imagine food is that short supply that there simply isn't enough to go around. You got a whole world's worth of canned goods. I'm thinking one large group would tend to hold up better than disparate little bands all over the place.
We sometimes forget that they are still ostensibly in full-on survival mode, which probably requires keeping other groups at a distance and which may even justify some of the moronic actions of moron Shane. But it's fun and easy to speculate on future politics and diplomacy, which is always the most interesting part of any apocalyptic novel. I think the smart thing is to gradually open up contacts with other survivors to pool security measures and skills. One group may have a doctor, another a skilled electrician. Both groups get stronger with an alliance or merger. In
Lucifer's Hammer, a key character was Harry the Mailman, who carved out a niche as a roving messenger, earning his keep by traveling from group to group to bring news and serve as intermediary for negotiations. In
World War Z, only a centralization of survivors was able to stem and eventually turn the tide against the hordes of zekes. That all seems pretty reasonable, or as reasonable as any tale of the apocalypse can get.
Internal politics will also be interesting. There will be conflicts between monarch wannabes (Will Patton in
The Postman, who employs Shane-types as his henchmen) and more democratic communities. I imagine one of the earliest conflicts will be for people of skills, with some using force and fear to retain them and others tempting them with greater freedom and power.