If Frontier has plans to implement a modkit, modders could take the feeders as base, exchange the models with those of fooliage and edit them so they would never run out of food. This way we wouldn't need any kind of keepers, or any human influence at all (except a keeper that delivers the animals). The only things that could ruin our wildlife dreams are:
Diseases: Since it is a zoo builder the way diseases spread and work could be entirely different from how they work in real life, like animals not be able to heal over time and thus be completely dependent on vets. Just one sick animal could cause a devastating epidemic. If dinos get sick in JWE, and you don't intervene, they are 100% doomed and somehow even manage to infect animals in other enclosures on the other side of the map.
Unstable Population: If someone has plans to create a truly wild paradise for the long term, it will probably end with a total overpopulation of carnivores that eventually starve to death because they already hunted everything they could. The map size seems to be decent, but it probably won't be big enough for a stable population.
Poop: If the devs never intended to let poop vanish over time, your wildlife dreams will eventually drown in an endless sea of poop. The end.