I woulden't give the series such a short lifespan at all. I think it should have at least a couple of seasons, and can probably do quite well. If the movie series weren't profitable, they woulden't have made a tv series, after all, much research of the market and potential for profit go into any decision made on this level of magnitude (making an animated tv series can be expensive.) Anyway, what we've seen so far is quite good for an animated tv series (in my opinion.)
Besides, there are many, many things that could happen to the characters, even though the options are limited without technology, money, or civilization. Some possibilities include:
1. One of the characters gets injured, either in an accident, or by a predator. One possibility could be that Tricia gets injured while playing with the main characters (gets hit by a rock/hard piece of fruit.) I know this sounds cold-hearted (i'm writing about an infant being injured), but the repercussions could make for a good episode; to make it more interesting, what would happen if Cera were indirectly, unintentionally responsible for Tricia being hurt? (She suggested the game, and hit the projectile, like in the show's introduction.) How would Tria react? How would Cera's father react?
2. Chomper's parents come looking for him (since we haven't seen the first two episodes, we don't know if they would do this, or what the exact situation is.)
3. Show more of each of the character's pasts; they already did this with Ruby in episode 3.