If you always got a success, so why do you need a failure ?
Your fail only useful when you use it as a tool for analyzing when you make a new strategy to avoid repeat the same thing (failure). With a good strategy, arranged in a good way by considering the experience that was learned from failure, hopefully will get a big success.
Failure could be use as a best lesson learn (to not repeat the same way).
Evolution use a failure as a model to fix it.