Of course youth should be valued over extreme age.
In most cases, young people do most of the work that keeps the world turning, and they're also capable of reproducing. We could say that changes with sick people, they aren't working as much or reproducing, but let's say a 40 year old who needs a new heart may already be a parent of a young child, while a 70 year old is merely a grandparent. The parent is more needed.
Plus, we're going to have way too many old people on our hands here very shortly, and it disgusts me, because they're one hell of a fucking narcissistic generation as it is, they think everything is owed to them, and I'm not sure how that is going to play out in reality when there are more elderly than there are young.
I say we have to let them die. Especially Dick Cheney for fuck's sake (though he probably was favored because he is Dick Cheney ).