In churches acclimated to failure, gifted leaders will likely take a background role as the church reverts to maintaining only the bare minimum sustenance roles. In times of failure, it takes a great deal of energy to desperately hang on to whatever is sustaining the organization. When failure is followed by failure, each successive failure causes an even greater downturn of energy. Even the greatest coach is only as good as his team. Unfortunately, disillusioned and burnt-out teams often would rather rebel and change leaders than look at themselves and make needed changes.
Failure causes members to leave.
In the process, they will also add to the frustration of those in the church they left. First, whether you experience success or failure, there's always problems in either case. Second, even the greatest successes won't insulate you from the grind of dealing with problems. Third, effective ministry is not measured by whether or not you have problems. You will have problems.