Sometimes experience can even be harmful. Suppose an individual or a team encountered one situation, and worked very hard to explore, figure out a viable "attack" to solve it, perhaps after a number of failures. Now they have experience. Suppose they're hired to help another project which is in a similar situation -- perhaps instead of repeating what they did the first time, instead of exploring they jump straight to applying the solution that worked before. If the situation is similar but not enough for the same solution to work, then maybe the outcome is going to be worse than if inexperienced folk with reasonable problem solving skills were thrown at it.