I might not have a full picture of the full game, but to me so far it seems as if everything can be gathered in a close proximity to your tribe homestead. This leads to all tribes being totally independent and self sufficient.
There is no tangible effect of starvation/thirst that I have noticed, except faster health regen. I hope there will be a very heavy penalty for starvation/thirst when cooking is released. Like -80% efficiency in all skills and -80% skill gain and possibly even skill decay. I would not care for thirst/hunger if it only affected quality of crafted items, since I spend time just skilling crafting and I do not care about the hundreds of helmets I create as long as I gain skill ups at non penalized rate.
If there was a clear need for food, then there would be a bigger need for hunting/fishing.
There should be highly sought after materials that are rare and only found in specific regions. If there was a very high quality metal found in one specific region, tribes of that region would be able to gather it and trade it for other highly sought commodities, that are only found in other regions. And when trade commences on a large scale, then pvp might have a meaning as a means of stealing the valuable commodities.
There could be rare, powerful mutants/animals that you can skin/buthcher/etc for superior meat/skins/bones/trophies that require tribes to gear up combat skilled tribe members with the absolutely best equipment they can craft so they can bring back fabulous components that you can use to craft items that will give, for instance, trophies that give tribe buffs, food that is better/longer lasting than other food, bones that can be used to produce the best bone armor/bone tools/bone weapons in the game.
Since such monster spawns would be on the rare side, there would be a clear incentive to fight over those spawns or people would try to steal the items from the monster slayers. It would result in a race towards the safety of the tribelands, while other tribes are hunting them for their precious goods. This would allow excitement and a meaningful/logical goal for pvp instead of just having noob ganking.