[pasbesoin]

One very bright guy maybe still in his 30's.

Otherwise, 40's and 50's.

Not just experience. Problem solving, including creative thought. Practicality. Reduction in B.S. -- although that can cut both ways, with age, depending upon the person.

P.S. A lack of ego/defensiveness can also be very helpful. It becomes about fixing the problem, not excessively defending one's turf and an unrealistic reputation.

P.P.S. Younger people can have these things, and be quite excellent. Maybe a bit more insecurity is still common -- whether overt or over-compensated for in expression. I spent a lot of time in BigCorps; that may have influenced the demographics of my environment and thus my observations.