"It has taken care of us very well."
Past performance is no guarantee of future performance. Nature also took quite good care of the dodo, the Tasmanian tiger, etc.
We are part of an ecosystem. I guess we're going to find out how much of that system we can destroy until we ourselves go extinct, or figure out a way to exist outside of the food web. Remember, just because you don't care about some little tree frog somewhere doesn't mean that the symbiotic and inter-connected nature of the system doesn't care.