There is more to damages in a civil suit then just loss of income, like pain and suffering and loss of consortium. For example if a drunk driver jumps a curb and runs over a stay at home mom out pushing her baby in a carriage and kills the mother and child should be not be held financially responsible if they die after a few months in the hospital? Shouldn't their estates be able to use for their pain and suffering and then have the money go through the estate like any other money? Otherwise you're effectively rewarding the wrong doer for killing v. just injuring someone.
Also the husband normally has a claim for the loss of his wife's companionship regardless of economic loss.
In NY at least the deaths of infants are really not worth much from a money standpoint-you really can't prove any economic loss so if the baby did not suffer it's not worth much money-but from a real world standpoint the loss of a baby is probably the most awful thing any of us could imagine.
A buddy of mine lost a child to medical malpractice (very clear malpractice, in fact the doctor admitted as much to him and several people), I told him that personally I didn't think the money was worth reliving the whole thing again anyway. I would have referred the case out to another attorney as I would have been too upset to handle it, but he and his wife agreed it wasn't worth the heartache tobring the lawsuit.