Good question. The prime difference - I believe - is that no creature can dominate a complex natural ecosystem, and they rarely use non-renewable resources. No one is in control, yet everything is kept in balance by grazers and predators. In other worlds it is a self regulating system. Sometimes even these stable systems tend to collapse too (because of climate change, or one species suddenly becoming dominant) but then they reorganize and start again. Collapse is not unknown to nature, but times of homeostasis lasts much much longer in between resets than in human societies.