Interesting ideas, and I think it might work. Because either we act as termites eating our own homes, or cultivate and expand as a whole. If left alone jungles expand, and dead materials create more life, unlike human waste. And your universe could also be islands. And then have the same idea, except you can run out of islands, and then your culture dies, if it hadn't mastered the trick to grow more nature instead of eating it all up.

Be sure to check my other game ideas, because there I worked some other very similar ideas out.