well, i don't quite agree. would you say the same thing if there were three dumb and deaf 90-year-old people with no hands and eyes? probably not. so, there is some sort of evaluation that we have to make to choose people. i agree that a it is possible for the above described person to say just one word and turn the whole course of humanity around, and that the healthy and smart person can die from tb in few weeks because he didn't get his shots when he was a kid... but what are the chances?
maybe my choices weren't quite right because i don't understand the life quite so well, but i don't think the randomness is the answer. otherwise dinasours would have survived till now.
plus, what if there are two exactly identical people with the only difference of that one knows how to cook and the other doesn't. would you still apply a random pick to them?
i know, morally you might not feel right about make such choice, even if one person is almost a mummy, but if you have been chosen as the sole chooser, then there is already something wrong with the system and your morals wouldn't probably apply, or porduce the right (expected) result, at that time.