Inexperience is the new Competency?

Past experience is often considered to be a proxy for future performance. After all, when there is no single perfect way to forecast someone’s future performance, the best you can do is to look at the past track record and extrapolate it! However, experience will only tell that if the given person were to undergo similar experience once again, would they achieve similar results? But, how do you know that experience is not really getting in the way of future success?