[cguess]

And a lot of times that can be true, being young and gifted is amazing, but doesn't overcome years of experience in the trenches. Sure you may be able to work a 24 year old brilliant dev 80 hours a week and the 54 year old may want to leave by 6 every day, but if you hire right you'll get the same amount of work out of them, the 54 year old will just need a lot less effort to get to the same place.