Nature as we experience it now took millions of years to get to this point. The "working" state we have now is a result of a great many things coming together into a - for us humans - local minima that just happens to support life as it exists. And yet for humans in particular, things still don't work that well per se. There are generic diseases, mutations, etc that we have found varying ways to offset artificially. We - and all other animals - also get old, which is just short for all systems breaking down over time. Maybe all that can be considered "working" at a macro level, but it sucks at the micro.