Lets use the logic of ecosystems alright...
From POV of the Planet: Lavos = a parastite.
Krakkers = Baby Lavos
Baby Lavos + Time => Lavos
Therefore: Krakkers + Time => Lavos
Furthermore: Krakkers + Time => Parasite
Now before these Krakkers grow they need resources. And until they reach certain age they will need energy and resources and suck it out of the host. The Host is not eachother or Lavos, but indeed it is the Planet... plus why would they leave if they did not have to? Explain that. Why should the Krakkers leave their host and resources. Using our ecosystems... animals and parasites take advantage of resources as mush as possible. Plus at least one of them (the strongest male if Lavos has gender) will stay and make the Planet their home. This cycle will continue, and eventually the rest of the animal won't have energy, because these Krakkers will grow to Lavos, who will absorb energy, who will give birth, whose spawn will grow and consume energy, and etc.
That is how natural ecosystems work... now explain how the Planet can counter it.